Laxton Robert, Author at Tomsaunders https://tomsaunders.co.nz/author/robert-laxton/ Blog about the chemical ecology and taxonomy of parasitoid wasps in New Zealand Wed, 20 Nov 2024 14:48:23 +0000 en-US hourly 1 https://wordpress.org/?v=6.6.1 https://tomsaunders.co.nz/wp-content/uploads/2024/08/cropped-bee-161866_640-32x32.png Laxton Robert, Author at Tomsaunders https://tomsaunders.co.nz/author/robert-laxton/ 32 32 Benefits of Using Wasps as Pest Controllers https://tomsaunders.co.nz/benefits-of-using-wasps-as-pest-controllers/ Wed, 20 Nov 2024 14:48:22 +0000 https://tomsaunders.co.nz/?p=100 What do we know about wasps? It’s a question we hear more often than not. We aren’t talking about Wasp Solitaire now. We leave this popular game for entertainment at […]

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What do we know about wasps? It’s a question we hear more often than not. We aren’t talking about Wasp Solitaire now. We leave this popular game for entertainment at NZ online casinos. We’d like to overview the situation with wasps in New Zealand, those bad guys with painful stings.

One must agree that wasps are quite demonized. These insects may interrupt picnics as they can be found in beer mugs and fruits. Their bite is very painful and can even cause an allergic reaction. A single wasp flying around you is quite terrifying.

The New Zealand beech forests are the habitat of the biggest populations of ground-nesting wasps – Vespula wasps. They are also known as the common or German wasps. So it’s no wonder that they get a lot of attention. Any of it is hardly positive. But such a bad reputation is not deserved. Some types of wasps can be useful in crop pest control. Some of New Zealand’s hort industries may benefit from it.

Wasps in New Zealand

There are over 30,000 different wasp species worldwide. Some of them have funny names, like sand wasps and fairy wasps. Others are known as fig wasps, chalcid wasps, and gall wasps. We’ve even heard about tarantula hawks, and they are also wasps. Some of them, like yellow jackets and hornets, are social and live in hives. Others are solitary and live alone.

Unlike bees, which only eat pollen and nectar from plants, wasps have the digestion of an ostrich. These pollinators feed on nectar and pollen while also eating other insects, like caterpillars and flies. This means they can also be beneficial for controlling pest populations.

Common wasps arrived in New Zealand in cargo ships from Europe in the middle of the past century. The new habitat turned out to be suitable for their life cycle, so that the wasps spread.

Paper wasps (Polistes) and ground-nesting wasps (Vespula) aren’t native to NZ. But unlike honey bees and bumblebees, they are active predators of other insects. They have the same food as native birds and lizards. In beech forests, wasps can also affect the populations of some endemic insects. They periodically terrorize managed beehives. That is why NZ authorities are making huge efforts to exterminate social wasps.

But you should know that these wasps eat insects, which cause major harm to us, too. There is a lot of evidence that wasps – especially Polistes, which are considered the major predators of caterpillars – may be effective at controlling crop pests.

Beneficial Predators

In one of the recent studies in the Midwestern USA, wasp colonies were moved into a fully screened cage with broccoli plants. Then, researchers added caterpillars to determine whether the presence of wasps affects pest consumption of broccoli plants.

The wasps ate all the caterpillars within a few hours. They were clever, too. The wasps followed people as they put the caterpillars on the plants. In fact, some wasps were able to sneak into the control plants from which they were excluded.

The researchers revised their controls and re-ran the study. This time, they used a different species of Polistes and kale plants. In a week, all caterpillars from kale plants were eliminated.

The results are obvious. Not only can wasp colonies be moved to a new location, but they are also active predators of crop pests. When Polistes were excluded from the plants with caterpillars, pest damage increased significantly. When wasps hunted on caterpillars, the crops prospered.

Like any other wasps, Polistes can sting if someone disturbs their nest. But unlike Vespula, they build small nests under the dripstones of houses. It’s relatively easy to remove them and relocate them to another spot.

People can distribute Polistes wasps around a crop field by relocating their nests. The special boxes serve as a buffer to reduce the chances of disturbing the nest and being stung.

Pest Control Potential

When watching wasps long enough, you can note that they carry pests away from your home garden, local park or field. So, could Polistes be used for pest control in New Zealand? The research suggests that they can be used as a biocontrol tool to eliminate garden varmints. However, additional research is required to find out how effective that might be. The NZ researchers should ensure they are targeting only pests and don’t affect local breeds.

This is not the first study to reveal the benefits of social wasps. Apart from pest control, wasps can spread yeasts on grapes. This is one of the ways to improve the quality of wine. Wasps also pollinate flowers effectively. Their venom is widely used in medicines, and research has shown that it can be a part of a possible cancer treatment.

In Conclusion

Overall, we are sure that wasps should not be considered as varmints. Their social behaviors are pretty complex. Did you know that they were the original paper manufacturers? If not, here is the fact. They turn dry wood, paper or cardboard into pulp with their saliva. That way, they create the nest cells where their spawn will grow.

Perhaps sooner rather than later, we will learn how to use them as biocontrol agents targeting crop pests. This method will allow people to reduce reliance on pesticides. Like wasp enthusiasts, we’d like to think their ability to control pests on various crops might one day change their reputation.

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Climate Change and its Impact on Parasitoid Wasps https://tomsaunders.co.nz/climate-change-and-its-impact-on-parasitoid-wasps/ Tue, 13 Aug 2024 14:21:45 +0000 https://tomsaunders.co.nz/?p=58 Changing climatic conditions are having a significant impact on ecosystems around the world, and parasitoid wasps are no exception. These insects, which play a key role in regulating pest populations […]

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Changing climatic conditions are having a significant impact on ecosystems around the world, and parasitoid wasps are no exception. These insects, which play a key role in regulating pest populations and maintaining ecological balance, can experience both positive and negative effects from climate change. In this article, we look at how changes in temperature, humidity, and other climatic factors are affecting parasitoid wasps and what implications this may have for ecosystems.

Changes in Temperature

Temperature is one of the most significant factors affecting the life cycles of parasitoid wasps.

An increase in average temperature can accelerate the development of parasitoid wasp larvae and adults. This can lead to more frequent generations per year, which increases their numbers and potentially increases the effectiveness of pest control. However, too high temperatures can also have negative consequences. For example, extreme temperatures can affect egg and larval survival rates, which can reduce overall wasp numbers.

Rising temperatures may lead to the expansion of the range of parasitoid wasps into new regions. This may create opportunities for colonization of new areas, but may also promote competition with native species and disrupt existing ecosystem balances. In addition, range shifts may facilitate the introduction of new parasitoid wasps into ecosystems where they have not previously been found, which may affect native pests and other ecosystem components.

Changes in Humidity

Humidity affects parasitoid wasps through its effects on their habitat and resources.

Changes in moisture levels can affect vegetation and water availability, which in turn affects the abundance of parasitoid wasp host insects. For example, an increase in humidity can promote plant growth, which can lead to an increase in insect pest populations, providing more resources for parasitoids. On the other hand, too much humidity can lead to the spread of diseases and fungi that can negatively affect wasps.

Humidity also affects the behavior of parasitoid wasps. For example, when humidity is high, they may seek drier breeding sites or look for other ways to adapt to changing conditions. Changes in humidity may also affect their ability to find hosts, especially if the ecosystem conditions in which parasitoids and their prey interact change.

Changing climatic conditions and food resources

Climate change can affect the availability of food and other resources that parasitoid wasps need to survive and reproduce.

Climatic changes can affect host insect populations of parasitoid wasps. For example, increases in temperature and changes in precipitation can alter host life cycles, which can affect their interactions with parasitoids. Some host species may reproduce faster or slower, which in turn affects the availability of food for parasitoid wasps.

Climate change may also affect the resources that parasitoid wasps use to lay eggs and develop larvae. For example, changes in vegetation or food availability for adult wasps may affect their ability to find suitable breeding sites and maintain their populations.

Adaptation and Evolution

Parasitoid wasps are highly adaptable, allowing them to cope with changing climatic conditions.

Gradual changes in climate can lead to evolutionary adaptations in parasitoid wasps. These may include changes in life cycles, behavior, and morphology that help wasps better adapt to new environments. For example, they may develop new host-finding strategies or alter their reproductive cycles to better suit changing environmental conditions.

Parasitoid wasps can modify their behavioral strategies in response to climatic changes.

For example, they can adapt their methods of finding food or breeding sites in response to changes in temperature and humidity. These behavioral changes help wasps make efficient use of available resources and maintain their populations in the face of climate change. Changing climatic conditions have profound effects on parasitoid wasps and their ecosystems. Changes in temperature, humidity, and resource availability can lead to both positive and negative consequences for these insects. Understanding these influences and the adaptive mechanisms of parasitoid wasps is important for developing strategies to protect ecosystems and manage agricultural resources in the face of climate change. Effective observation and research on these processes will help predict potential changes in ecosystems and develop measures to maintain and restore them.

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How Parasitoid Wasps Impact Ecological Balances https://tomsaunders.co.nz/how-parasitoid-wasps-impact-ecological-balances/ Thu, 08 Aug 2024 14:15:13 +0000 https://tomsaunders.co.nz/?p=52 Parasitoid wasps play a crucial role in maintaining ecological balance in natural ecosystems. Their unique lifestyle of parasitizing other insects makes them key players in complex food chains and natural […]

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Parasitoid wasps play a crucial role in maintaining ecological balance in natural ecosystems. Their unique lifestyle of parasitizing other insects makes them key players in complex food chains and natural regulators of insect pests. In this article, let’s look at how parasitoid wasps influence ecological balances and how their activities contribute to ecosystem resilience.

Role of Parasitoid Wasps in Food Chains

Parasitoid wasps occupy a special place in ecosystem food chains as intermediate predators. They control the numbers of their victims – the insects on which they parasitize, which prevents excessive reproduction of pests and maintains a balance between different trophic levels.

The main role of parasitoid wasps is to control the numbers of insects that may become plant pests. For example, many wasp species parasitize caterpillars, aphids, and beetles that can cause severe damage to crops and woodlands. By limiting populations of these pests, parasitoid wasps prevent their mass reproduction, which helps to maintain healthy ecosystems.

The impact of parasitoid wasps on the ecosystem goes beyond pest population control. Their presence can also affect other insect species, including competitors and potential predators. For example, a decrease in pest populations due to wasps may lead to an increase in populations of other insects that are not under such pressure. Thus, parasitoid wasps affect the balance of the entire insect community by regulating interactions between different species.

Ecological Importance of Parasitoid Wasps in Different Habitats

Parasitoid wasps successfully adapt to different habitats and fulfill their functions in both natural and anthropogenically altered ecosystems.

In forests, parasitoid wasps play a critical role in maintaining the health of woody vegetation. They control the numbers of insects that can damage trees, such as bark beetles and caterpillars. Without the presence of parasitoid wasps, populations of these pests could multiply uncontrollably, resulting in significant tree losses and deterioration of forest ecosystems. Wasps also contribute to forest biodiversity by maintaining a balance between different insect species.

In agricultural ecosystems, parasitoid wasps are often considered as biological agents that can replace or supplement the use of chemical pesticides. They help to maintain balance in agroecosystems by controlling the abundance of pests such as aphids and other insects that damage crops. The use of parasitoid wasps helps to reduce dependence on chemical defenses, which benefits the sustainability of agricultural systems and reduces environmental stress.

In urban settings, parasitoid wasps can also serve important functions by regulating pest populations in gardens, parks and green spaces. For example, wasps can control aphid populations on ornamental plants, which contributes to the health of urban flora. The impact of wasps on urban ecosystems helps to maintain ecological balance and reduce the need to use chemical plant protection products.

Adaptations and Success of Parasitoid Wasps

Parasitoid wasps show a high degree of adaptability, making them successful agents of natural control.

Many species of parasitoid wasps have a high degree of specialization on specific hosts. This allows them to efficiently find and infect their victims while minimizing competition with other parasitoid species. This specialization helps to maintain stable populations of both wasps and their victims, which plays an important role in ecological balance.

Wasps exhibit complex behaviors that help them find their hosts even in difficult environments. For example, they can use chemical signals emitted by plants or prey to pinpoint the location of their hosts. These adaptive abilities allow wasps to perform effectively in a wide variety of ecosystems.

Parasitoid wasps are important regulators of ecological balances in a variety of ecosystems. Their ability to control insect pest populations and interact with other species makes them key players in food chains and natural processes. The impact of wasps on forest, agricultural, and urban ecosystems demonstrates their indispensable role in maintaining the health and sustainability of natural systems. Given the ecological importance of these insects, their protection and proper utilization in biological control represent important challenges for biodiversity and ecosystem stability.

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Ecological Importance of Parasitoid Wasps in New Zealand Forest and Agricultural Ecosystems https://tomsaunders.co.nz/ecological-importance-of-parasitoid-wasps-in-new-zealand-forest-and-agricultural-ecosystems/ Fri, 02 Aug 2024 14:09:28 +0000 https://tomsaunders.co.nz/?p=49 Parasitoid wasps play a key role in New Zealand ecosystems, particularly in forested and agricultural areas. These insects perform important functions in the natural regulation of insect pests, contributing to […]

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Parasitoid wasps play a key role in New Zealand ecosystems, particularly in forested and agricultural areas. These insects perform important functions in the natural regulation of insect pests, contributing to ecological balance and ecosystem health. In this article, we review the ecological importance of parasitoid wasps, their impact on New Zealand’s forest and agricultural ecosystems, and their role in biological control of pests.

Role in Forest Ecosystems

New Zealand’s forests, known for their biodiversity, need natural mechanisms to control insect pests that can threaten tree and plant health. Parasitoid wasps are some of the main agents that support this control.

Control of Insect Populations
In forest ecosystems, parasitoid wasps control the populations of harmful insects such as caterpillars, aphids, and bark beetles. These insects can significantly damage woody species, resulting in weakened trees and reduced ability to resist disease and other stressors. Parasitoid wasps, by laying eggs in or on the bodies of their victims, effectively limit their populations, preventing mass reproduction of the pests.

Maintaining Biodiversity
By controlling insect pest populations, parasitoid wasps help maintain forest biodiversity. Fewer pests mean that plants and trees have more resources to grow and develop, which in turn supports the diversity of species in the forest ecosystem. Healthy forests filled with a variety of plant and animal species are more resilient to outside influences and climate change.

Relationship to Plants
Parasitoid wasps also interact with plants, attracting them with chemical signals or using them to host offspring. Some plants secrete specific substances that attract wasps when they are attacked by pests. In this way, plants can indirectly attract wasps, which helps regulate the number of insect pests on those plants.

Role in Agricultural Ecosystems

In New Zealand agriculture, parasitoid wasps are important allies of farmers in pest control. Under intensive farming and horticultural conditions, these insects help reduce reliance on chemical pesticides by providing a sustainable method of pest control.

Biological Pest Control
In agricultural ecosystems, parasitoid wasps are used as a natural way to control insect pests. Many wasp species, such as Braconidae and Ichneumonidae, specialize in killing certain pests that cause significant damage to crops. For example, some species of braconids parasitize caterpillars that destroy the foliage of fruit trees, thus reducing crop damage.

Reducing Pesticide Use
The use of parasitoid wasps in biological control helps to reduce the use of chemical pesticides. This has several important consequences: reduced environmental pollution, increased disease resistance in ecosystems, and improved quality of agricultural products. A healthy agroecosystem with parasitoid wasps is more sustainable and economically beneficial as farmers can spend less on chemical plant protection.

Increased Yields
Effective control of pest populations with parasitoid wasps helps to increase crop yields. Healthy plants that have not been attacked by pests can develop fully and produce higher yields. This is especially important for gardeners and farmers of fruits, vegetables and cereals.

Examples of Successful Use of Parasitoid Wasps

New Zealand has a long history of successful use of parasitoid wasps in biological control. One such example is the use of wasps of the genus Encarsia to control whitefly in greenhouses. These small chalcidoids successfully parasitize whitefly larvae, reducing their population and preventing damage to plants. This has reduced the use of insecticides in greenhouse farming and improved the quality of vegetables and fruits grown.

Another example is the introduction of parasitoid wasps to control leaf beetles, which were accidentally introduced to New Zealand and have become a serious threat to native trees. These wasps, which specialize in specific species of leaf beetles, have been effective in reducing their numbers and have helped restore the health of affected forests.

Parasitoid wasps play an important role in maintaining ecological balance in New Zealand’s forest and agricultural ecosystems. Their ability to control insect pests makes them indispensable participants in natural and agroecosystems. The use of parasitoid wasps in biological control helps to reduce reliance on chemical pesticides, maintain biodiversity and improve ecosystem resilience. These insects are an important element in the sustainable management strategy for New Zealand’s natural and agricultural resources.

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Parasitoid Wasps and Biological Control https://tomsaunders.co.nz/parasitoid-wasps-and-biological-control/ Tue, 23 Jul 2024 14:00:00 +0000 https://tomsaunders.co.nz/?p=46 Biological pest control is an important strategy in agriculture and environmental protection to keep pest populations at acceptable levels with minimal use of chemical pesticides. One of the key components […]

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Biological pest control is an important strategy in agriculture and environmental protection to keep pest populations at acceptable levels with minimal use of chemical pesticides. One of the key components of this strategy is parasitoid wasps, which have proven to be effective in controlling various pest species. In this article, we will look at the role of parasitoid wasps in biological control, their features and advantages over other methods of pest population management.

Parasitoid wasps play an important role in natural ecosystems by controlling insect populations and preventing overbreeding. In agricultural and forestry settings, they are used as effective biological control agents, reducing the need for chemical pesticides and maintaining ecological balance.

Advantages of using parasitoid wasps in biological control

Ecological safety

Parasitoid wasps are natural enemies of many pest species and therefore represent an environmentally safe control agent. Unlike chemical pesticides, they do not pollute the environment or harm other, non-target organisms. This makes them ideal candidates for integrated crop protection and sustainable agriculture.

Specificity in host selection

Many species of parasitoid wasps are highly specific in their host selection, allowing them to effectively control certain pest species without affecting populations of other insects. This specificity reduces the risk of unintended consequences, such as the destruction of beneficial insects or the development of resistance to biological control.

Long-term action

Parasitoid wasps are able to maintain their populations for a long time after introduction into an ecosystem. This provides long-term effects on pest populations, often without the need to reintroduce wasps or additional interventions. These persistent parasitoid populations create a natural control, keeping pest populations low.

Reduced pesticide costs

The use of parasitoid wasps in biological control can significantly reduce the need for chemical pesticides, which in turn reduces plant protection costs and reduces negative environmental impacts. It also improves ecosystem health and the quality of agricultural products.

Examples of successful use of parasitoid wasps

Aphids and Aphidius colemani
One of the best known examples of the use of parasitoid wasps in biological control is the control of aphids using Aphidius colemani wasps. These small wasps effectively control populations of various aphid species by parasitizing them and significantly reducing their numbers. They are often used in greenhouses and open fields to protect vegetable and ornamental crops.

Whitefly and Encarsia formosa
Another example of a successful application is the use of the wasp Encarsia formosa to control the whitefly, an insect that poses a serious threat to greenhouse crops. These wasps lay their eggs inside the whitefly larvae, causing them to die and reducing damage to plants. Encarsia formosa has been successfully used in various countries to protect greenhouse vegetables and ornamental plants.

Caterpillars and Cotesia glomerata
Cotesia glomerata wasps are used to control caterpillars, especially those that feed on cruciferous crops such as cabbage and broccoli. These parasitoid wasps lay their eggs inside the caterpillars and their larvae feed on the host’s tissues, resulting in its death. The use of Cotesia glomerata in agriculture helps reduce damage caused by caterpillars and reduces the need for chemical insecticides.

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Evolutionary Adaptations of Parasitoid wasps of New Zealand https://tomsaunders.co.nz/evolutionary-adaptations-of-parasitoid-wasps-of-new-zealand/ Sat, 06 Jul 2024 13:52:00 +0000 https://tomsaunders.co.nz/?p=42 New Zealand, with its unique flora and fauna, is an interesting site for studying evolutionary processes occurring in isolated ecosystems. Among the many species that have adapted to local conditions, […]

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New Zealand, with its unique flora and fauna, is an interesting site for studying evolutionary processes occurring in isolated ecosystems. Among the many species that have adapted to local conditions, parasitoid wasps occupy a special place, playing an important role in regulating insect populations. In this article, we will examine what evolutionary adaptations have allowed parasitoid wasps to successfully survive and reproduce in the specific conditions of New Zealand.

Isolation and specificity of New Zealand’s environment

New Zealand is located in the southwestern Pacific Ocean, at a considerable distance from other major landmasses. The isolation of the islands over millions of years has resulted in unique ecosystems that lack many species typical of other parts of the world. Parasitoid wasps, both introduced and endemic, have had to adapt to this isolated environment.

As predators or parasitoids of other insects, these insects have had to develop strategies that allow them to hunt, reproduce, and compete effectively with other species in the face of limited biodiversity and a unique fauna.

Adaptations in host selection

One of the most notable evolutionary adaptations of parasitoid wasps in New Zealand is a change in their host preference. In an environment where the local fauna is very different from that of other continents, wasps had to switch to new hosts. This required significant behavioral and physiological changes.

Some wasp species have shown a high degree of plasticity in host selection, allowing them to parasitize insects not found in their natural range. Other species have developed a narrow specialization, adapting to one or more host species that have become their main food sources and breeding grounds.

Changes in reproductive strategies

Reproductive strategies have also undergone changes. With a limited number of hosts and strong competition, some wasp species have developed more efficient ways to reproduce. For example, increased fecundity or reduced larval development time allows these insects to replenish their populations more quickly and compete more effectively with other parasitoids.

Other wasp species have adapted to seasonal changes in New Zealand conditions. For example, they can synchronize their reproductive cycles with the presence of certain host species that are only active at certain times of the year. Such seasonal adaptations allow wasps to avoid competition and increase their chances of successful reproduction.

Evolution of predatory behavior

The predatory behavior of parasitoid wasps has also undergone changes under pressure from the specificity of New Zealand ecosystems. Some wasp species have evolved more sophisticated host search and capture mechanisms. For example, they can target specific chemical signals released by their hosts or the plants on which these hosts live. These signals play a key role in enabling successful host search and capture in environments where traditional hunting methods may be less effective.

In addition, when competition for a limited number of hosts is high, some wasp species may exhibit aggressive behavior towards other parasitoids preying on the same host species. This aggressive behavior may include directly attacking competitors or using chemicals to deter other wasps from host habitats.

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Predators and parasites https://tomsaunders.co.nz/predators-and-parasites/ Fri, 28 Jun 2024 13:45:00 +0000 https://tomsaunders.co.nz/?p=36 To most people, parasitic wasps are invisible. Their life cycle is quite remarkable, but they remain almost unknown outside the world of Hymenoptera, the entomologists who study wasps, as well […]

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To most people, parasitic wasps are invisible. Their life cycle is quite remarkable, but they remain almost unknown outside the world of Hymenoptera, the entomologists who study wasps, as well as ants, bees, and other members of the Hymenoptera.

Parasitoid wasps need a host to complete their development. They are a cross between parasites and predators: like parasites, they feed on their host and, like predators, eventually kill it.

Different groups of parasitic wasps attack different groups of hosts. Wasps from the subfamily Aphidiinae feed exclusively on aphids. Aphids can reduce yields and spread plant viruses, which requires the use of harmful pesticides. Since the host dies after encountering the parasitoid, these wasps are used for biological control and help to naturally control aphid populations.

Classification

Biological control only works if we know what we are controlling and what we are controlling it with. Taxonomists, like me and my colleagues, study insects (in my case, aphids and their parasitoids) and classify them into species.

The systematics of living things is mainly based on their morphology. We still actively use this method, taking these tiny insects apart and looking at them under a microscope to find differences or similarities and determine which species we are looking at. When you’re working with creatures that are one to two millimeters long, it can be intimidating.

Technologies such as DNA barcoding, developed by biologist Paul Hebert, and DNA sequencing techniques, especially next-generation sequencing, have accelerated this work. I can now extract the DNA of a wasp and determine what species it belongs to without having to visually examine the sample.

To do this, we need a comprehensive reference library of DNA sequences, which is a huge and ongoing task. In online databases containing reference sequences, some groups are better represented than others. Ideally, I would use both morphological and molecular data in my work and avoid any misidentifications.

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Variety of wasps https://tomsaunders.co.nz/variety-of-wasps/ Tue, 25 Jun 2024 13:50:00 +0000 https://tomsaunders.co.nz/?p=39 Parasitoid wasps seem to be more diverse than expected. Beetles have long been the “official” insect order with the largest number of species. However, the Hymenoptera (wasps, bees, sawflies and […]

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Parasitoid wasps seem to be more diverse than expected. Beetles have long been the “official” insect order with the largest number of species. However, the Hymenoptera (wasps, bees, sawflies and ants) are actually more species rich, with a huge number of mysterious and still unknown species.

Ants often help to protect aphids from predators and parasitoids, and in return collect honeydew from them. Ladybugs are voracious predators of aphids and can also be used for biological control. They are also the curse of the hymenoptera because they eat aphids, parasite larvae and everything else.

A parasitized aphid is called a mummy, and it is basically a parasitoid larva or pupa of a wasp that develops in the dead skin of an aphid. At the next stage, the adult wasp emerges and goes about its business: eating, mating, and if it is a female wasp, looking for new hosts to lay eggs and start the cycle again.

Cryptic species

Cryptic species look very similar or identical to other species, but when their DNA is sequenced, there are clear differences in certain genes that indicate the presence of three or five species instead of one. Correct species identification is essential for proper conservation efforts.

In addition, correct species identification is important for applications such as biological control. Closely related and morphologically indistinguishable species of biocontrol agents may have different host requirements and, as a result, will not be effective in controlling the same pests.

It seems that the importance of biodiversity is finally being understood by a wider audience than scientists, and this is great news. Since much of our planet’s biodiversity is still hidden, we need to describe as many species as possible as soon as possible to be able to protect them in time.

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Life history and habits https://tomsaunders.co.nz/life-history-and-habits/ Fri, 21 Jun 2024 14:25:00 +0000 https://tomsaunders.co.nz/?p=61 The exact appearance of parasitoid wasps depends on the species. Most are extremely small (1 to 10 mm) and have brown or black bodies with long, thin antennae. However, some […]

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The exact appearance of parasitoid wasps depends on the species. Most are extremely small (1 to 10 mm) and have brown or black bodies with long, thin antennae. However, some species belonging to the family Ichneumonidae can be over 10 cm (4 inches) long and have a very long ovipositor (egg-laying structure), while Trichogramma spp. are very small, 0.25-1 mm (1/25 in) long.

In some species, the pupae are the most commonly observed life stage and look like rice grains on the surface of the host insect. Gardeners are more likely to see the results of parasites, such as aphid mummies, than the wasps themselves.

The exact life history of parasitoid wasps depends on the species, but most tend to be specialists that attack a single host insect species. Together, parasitoid wasps attack aphids, scale insects, scale insects, stink bugs, beetles, and caterpillars in various life stages. The parasitized aphids usually turn brown or black and have a swollen balloon-like appearance. After completing its development, the adult wasp emerges and leaves a round exit hole in the back of the dead aphid, called an aphid mummy.

Female wasps usually parasitize their hosts by paralyzing the adult insect or larva and laying eggs inside. After hatching, the larvae feed inside (endoparasite) or outside (ectoparasite) the host. After pupation, an adult wasp emerges inside or outside the host. Wasps that pupate externally often spin conspicuous pupal cocoons after they emerge from the host. Adults typically feed on nectar, pollen, and honeydew, and in many cases, parasitoid wasps require floral resources for pollen and nectar to maximize their effectiveness.

Parasitoids as biological control agents

Several species of parasitoid wasps are commercially available for the biological control of certain pests in fruits, vegetables and ornamental plants. One species, Aphidius colemani, is designed to control aphids in greenhouses and outdoor growing systems. Various Trichogramma spp. are available for the control of scale insect pests, including corn borer, scoopers, cabbage looper, worms, borers and cuckoo beetles.

In addition to these commercially available parasitoid wasps, natural populations of other species can effectively suppress populations of certain insect pests. Trissolcus spp. are important parasitoids of the eggs of the brown marbled bug (Halyomorpha halys). The entire development of the wasp from egg to pupa takes place inside the parasitized bug egg, which darkens as the wasp develops. One species in particular, the samurai wasp (Trissolcus japonicas), has been observed to parasitize 90% of brown marbled bug eggs. Colpoclypeus florus is another species of parasitoid wasp that attacks the caterpillars of scale insects. In 1992, this species was observed to parasitize approximately 80% of the larvae of leafhoppers in untreated apple orchards in Washington. In some cases, more than 50 C. florus can be produced from a single host. Maintaining natural populations of parasitoid wasps is possible through good conservation practices.

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Taxonomy of the Parasitoid wasps of New Zealand https://tomsaunders.co.nz/taxonomy-of-the-parasitoid-wasps-of-new-zealand/ Mon, 10 Jun 2024 13:06:00 +0000 https://tomsaunders.co.nz/?p=33 New Zealand, known for its unique biodiversity, is home to many endemic species, including parasitoid wasps. These insects play a key role in maintaining ecosystems by controlling populations of other […]

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New Zealand, known for its unique biodiversity, is home to many endemic species, including parasitoid wasps. These insects play a key role in maintaining ecosystems by controlling populations of other insects and preventing overbreeding. In this article we will look at New Zealand’s parasitoid wasp taxonomy, their classification, species diversity and their importance to the local ecosystem.

Parasitoid wasps: Main characteristics

Parasitoid wasps are a group of insects belonging to the order of webworms (Hymenoptera). These wasps lay their eggs on or inside the bodies of other insects such as caterpillars, beetles or aphids. The wasp larvae develop by eating their host, which eventually leads to its death. This behavior makes parasitoid wasps important natural regulators of pest populations.

Parasitoid wasps are divided into several families, each differing in morphology, behavior, and host specificity. Representatives of such families as Ichneumonidae (Ichneumonidae), Braconidae (Braconidae), Chalcidoidea (Chalcidoidea) and others are found in New Zealand.

Families of parasitoid wasps in New Zealand

Ichneumonidae
The family Ichneumonidae is one of the largest families of parasitoid wasps, with thousands of species worldwide. In New Zealand, members of this family play an important role in controlling insect pests. These wasps are characterized by a long body and a distinctive ovipositor structure, which is used to lay eggs in the host.

Ichneumonid species in New Zealand are highly specific in their host selection, making them effective agents of biological control. For example, one common species, Agrypon flaveolatum, specializes in parasitizing the caterpillars of various butterflies that damage agricultural crops.

Braconidae
The family Braconidae is also widely represented in New Zealand. These wasps tend to be smaller than the ichneumonids, but play an equally important role in the ecosystem. Braconids are characterized by a variety of life cycles and host types. In New Zealand, they often parasitize caterpillars and other insects that are pests of forests and agriculture.

Braconidae include species such as Apanteles glomeratus, which parasitizes squirrel caterpillars as an important factor in their natural control.

Chalcidoidea
Chalcidoidea is a broad superfamily of small parasitoid wasps, many of which are also common in New Zealand. These wasps are known for their miniaturized size and high efficiency in controlling insect populations. They often parasitize the eggs and larvae of other insects, preventing their development.

In New Zealand, chalcidoids play a key role in controlling pests such as aphids and small caterpillars. One well-known representative is Encarsia formosa, used for biological control of whiteflies in greenhouses.

Endemic and introduced species

New Zealand has a rich history of both the introduction of new species and the conservation of endemic fauna. Some species of parasitoid wasps have been introduced by humans to control invasive insects that threaten agriculture and local ecosystems. An example is the introduction of some species from the braconid family to control leafhoppers, which have no natural enemies in New Zealand.

Endemic wasp species also play an important role in local ecosystems by maintaining balance and preventing overbreeding of insect pests. For example, endemic species in the family Ichneumonidae specialize on local insect species, many of which are also endemic.

Taxonomic studies and their significance

Taxonomy of parasitoid wasps is an important area of research aimed at species identification, description and classification. In New Zealand, this research is of particular importance as the country has a unique fauna and flora. Describing new species and studying their biology and ecology helps to better understand how they interact with their environment and how they can be used in biological control.

Molecular techniques such as DNA analysis are playing an increasingly important role in taxonomic studies. They can clarify relationships between species, as well as identify new species that are difficult to distinguish on the basis of morphological characters. In New Zealand, such studies are helping to clarify the taxonomy of both endemic and introduced wasp species.

The taxonomy of New Zealand’s parasitoid wasps is a complex and important area of research that contributes to a better understanding of the role of these insects in ecosystems. The diversity of species, their adaptation to local conditions and their role in biological control of pests make parasitoid wasps key elements in maintaining ecological balance. Research in this area continues to expand our knowledge and opens up new opportunities for sustainable management of natural resources.

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