Malevolent Designer News - How A Parasitic Wasp Targets Adult Fruit Flies

Syntretus perlmani grub emerging from the side of a fruit fly

Scale bar: 1mm

Newly-discovered parasitoid wasp, Syntretus perlmani. Scale bar: 1mm.

Moore, L.D., Chris Amuwa, T., Shaw, S.R. et al. (2024)

New species of wasp ‘hidden in plain sight’ discovered by MSU researchers | Mississippi State University

The world of parasites is a world that creationists need to turn a blind eye to (and not one blinded by a parasitic worm) because it contains abundant examples of how an intelligence that designed parasites can only be regarded as some sort of malevolent sadist who designs ways to make living things suffer, often horribly and in especially ghoulish ways - the sort of ways that only a sick mind could dream up.

Creationist cult leaders are also probably reticent about discussing parasites, given their parasitic lifestyle, but that’s a different matter.

Within the world of parasites, there are fewer better examples of the casual cruelty that characterises it than those of the many parasitoid wasps that lay their eggs in the living bodies of their host species, where their larvae feed on the body of the host, often only killing it at the last moment and sometimes manipulating its victim or reanimating its dead body to protect the parasites within it.

Very many of these parasitoid wasps attack the larvae of other insects and gain the protection of the eventual cocoon their host makes before dying, so the wasp's reproductive cycle is linked to that of its host species.

Tell me all about parasitoid wasps and their modus operandi, with examples, please. Parasitoid wasps are fascinating and highly specialized insects known for their unique reproductive strategy, which involves laying eggs in or on other organisms (called hosts). The larvae that hatch from these eggs eventually kill the host, but unlike traditional predators, they live off their hosts for a significant portion of their life cycle before that occurs. Here’s an overview of their biology and behavior, including examples of well-known species.

General Characteristics of Parasitoid Wasps

1. Parasitism vs. Predation: Unlike true parasites (like fleas or ticks), which often coexist with their hosts without immediately killing them, parasitoid wasps kill their hosts as part of their life cycle. The wasp eggs are usually laid in or on the host, and as the larvae develop, they consume the host from the inside, eventually leading to its death.
2. Lifecycle:
   • Egg laying: Female parasitoid wasps inject or deposit eggs directly into or onto a host organism.
   • Larval development: After hatching, the larvae feed on the host's tissues, often avoiding vital organs to keep the host alive as long as possible.
   • Pupation: Once the larvae have fully grown, they pupate, often leaving the host's body to form a cocoon nearby or within the host’s remains.
   • Emergence: Adult wasps emerge, ready to find new hosts to continue the cycle.

Types of Parasitoid Wasps

Parasitoid wasps are divided into several families and species, often categorized by their target hosts. Some common families include Ichneumonidae, Braconidae, and Chalcidoidea.

Examples of Parasitoid Wasps

1. Ichneumon Wasps (Family: Ichneumonidae):
   • Example: Ichneumon eumerus.
     • These wasps lay their eggs in caterpillars or pupae of moths and butterflies.
     • The larva feeds on the host's body fluids, eventually killing it.
     • They play an essential role in controlling populations of agricultural pests.
   • Mechanism: The female Ichneumon wasp uses her ovipositor (a specialized structure that looks like a stinger but is used for laying eggs) to insert eggs into caterpillars. The eggs hatch, and the larvae consume the caterpillar from the inside, avoiding vital organs to keep the host alive until the larva is nearly mature.
   
   
2. Emerald Cockroach Wasp (Ampulex compressa):
   • Host: Cockroaches.
   • Modus Operandi: This wasp delivers venom to the cockroach’s brain, effectively turning it into a "zombie." The venom disables the roach’s escape reflex, making it easy for the wasp to lead the cockroach into a burrow. Once there, the wasp lays an egg on the cockroach’s body, and the larva consumes the still-living cockroach.
   • Unique behavior: The wasp injects venom into precise areas of the cockroach's nervous system, manipulating its behavior rather than killing it outright. The cockroach remains alive but unable to flee, providing a fresh, living meal for the developing larva.
3. Cotesia glomerata (Family: Braconidae):
   • Host: Cabbage white butterfly caterpillars.
   • Mechanism: These wasps lay their eggs inside caterpillars. The larvae grow, feeding on the caterpillar’s tissues. Interestingly, infected caterpillars often exhibit altered behavior—sometimes protecting the wasp pupae after they emerge from their bodies.
   • Behavioral manipulation: Once the larvae emerge from the caterpillar, they spin cocoons near the host, which is often still alive. The caterpillar may remain near the wasps, defending the cocoons from predators before eventually dying.
4. Tachinid Flies (Family: Tachinidae) (Fly, but behaves like a parasitoid wasp):
   • Hosts: Caterpillars and other insects.
   • Modus Operandi: These flies lay eggs on the exterior of their host. After hatching, the larvae burrow into the host, feeding internally until the host dies.
   • They are known to control populations of various crop pests like gypsy moths and Japanese beetles.
5. Trichogramma wasps (Family: Trichogrammatidae):
   • Host: Eggs of other insects, especially moths and butterflies.
   • Mechanism: These minute wasps (about 1 mm in size) lay their eggs inside the eggs of their hosts. The parasitoid larva consumes the embryo within the host egg, preventing the pest from developing into an adult.

Modus Operandi and Special Adaptations

• Venomous manipulation: Some parasitoid wasps use venom not just to paralyze or disable their hosts but to manipulate their behavior. For example, the emerald cockroach wasp alters the behavior of its host, allowing it to control the cockroach’s movements.
• Specialized ovipositors: Many parasitoid wasps have highly adapted ovipositors. These needle-like structures can inject eggs into hard-to-reach hosts, such as inside plant tissues, or precisely deliver venom and eggs into mobile hosts.
• Co-evolution with hosts: Many parasitoid wasps have evolved alongside their hosts, developing highly specific adaptations that allow them to parasitize only certain species. In turn, some hosts have developed defenses like thicker exoskeletons or immune responses to fend off parasitoid larvae.

Ecological Role

Parasitoid wasps are crucial for maintaining balance in ecosystems. They help control the population of pests, which is particularly important in agriculture. Many parasitoid wasp species are even used in biological control programs to reduce the need for chemical pesticides.

Conclusion

Parasitoid wasps are masters of biological control, using their unique life cycle to subdue and consume their hosts. They exhibit a range of fascinating behaviors, from venomous mind control to intricate strategies for egg-laying. Their presence in ecosystems helps maintain population balance, and in agriculture, they are invaluable allies against pests.

Most parasitoid wasps either lay their eggs in or on the caterpillar/grub stage of their victims or they sting and paralyze it to provide their own grubs with fresh food, but researchers at Mississippi State University have discovered a parasitoid wasp that is unusual in that it targets the adult stage of its host - in this case the fruit fly, Drosophila.

The wasp grub lives and grows inside the fly until ready to pupate when it emerges from the side of its host.

The discovery is the subject of an open access paper in Nature, and is explained in a Mississippi State press release:

New species of wasp ‘hidden in plain sight’ discovered by MSU researchers

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Creating a buzz in Nature this week, a Mississippi State biologist’s research has led to the discovery of a new parasitic wasp species with unusual biology in the Eastern U.S., opening doors for future research in fundamental biological processes.

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Associate Professor Matthew Ballinger’s article “Drosophila are hosts to the first described parasitoid wasp of adult flies” in the world’s leading science journal highlights the discovery of a new wasp from backyard fly traps, revealing a “spectacular example of undescribed biology hidden in plain sight.”

All known parasitoid wasps of flies attack and develop inside immature life stages, and despite 200 years of research on parasitoid wasps of Drosophila and other flies, we have never come across a species that attacks the adult stage, until now.

Associate Professor Matthew J. Ballinger, senior author.
Department of Biological Sciences
Mississippi State University, Mississippi State, MS, USA.

Logan Moore, Ballinger’s Ph.D. student who was the Nature article’s lead author, began the project by collecting infected fruit flies from his backyard in Starkville. The team then used a combination of field collections and public data to show the new species lives across the Eastern U.S. and infects one of the most studied animals in biology, the fruit fly Drosophila melanogaster.

Studying how parasites and pathogens influence Drosophila biology and behavior has helped researchers learn more about fundamental biological processes like immunity and reproduction. We’re excited to learn more about the new species, and we hope other researchers will begin their own projects to better understand its infection biology, ecology and evolution in the coming years [emphasizing the need for ongoing research investment in insect biodiversity and systematics]

Associate Professor Matthew J. Ballinger

Ballinger’s team collaborated with Scott Shaw, an entomologist and parasitoid wasp expert at the University of Wyoming, to formally describe the new species. Researchers also documented the wasp’s complete life cycle and provided instructions for others to raise adult wasps in the laboratory.

This work is part of Ballinger’s 2022 $805,682 five-year CAREER grant to study Spiroplasma, the beneficial bacterium that protects its fruit fly hosts against infection by parasites.

On the subject of that final sentence, ChatGPT4o gives the following information on the symbiotic role of the Spiroplasma bacterium:

In the context of parasitoid wasps, what information do you have on the role of the bacterium Spiroplasma? Spiroplasma is a genus of bacteria known for its diverse roles in nature, but one particularly intriguing interaction is its symbiotic relationship with some insects, including its role in defending hosts against parasitoid wasps.

Role of Spiroplasma in Host Defense Against Parasitoid Wasps

1. Defensive Symbiosis:
   In some insects, Spiroplasma bacteria live in symbiosis and can offer protective benefits, especially against parasitoid wasps. These bacteria can make their host insects more resistant to parasitoid attacks by actively interfering with the development of parasitoid larvae inside the host.
2. Mechanism of Protection:
   When a parasitoid wasp injects its eggs into a host infected with Spiroplasma, the bacteria can act against the developing wasp larvae. The exact mechanism of this defense is not completely understood, but it is believed that Spiroplasma produces toxins that target the wasp larvae or provoke immune responses that inhibit the wasp's growth. Essentially, the bacteria either directly kill the parasitoid larvae or weaken them to the point that they cannot successfully develop.
3. Specific Examples:
   • Drosophila melanogaster (Fruit Fly): One well-studied case is the interaction between Spiroplasma and the fruit fly Drosophila melanogaster. Certain strains of Spiroplasma have been shown to protect Drosophila against parasitoid wasps such as Leptopilina boulardi and Leptopilina heterotoma.
     • Leptopilina boulardi is a parasitoid that typically infects Drosophila larvae. When a Drosophila host infected with Spiroplasma is parasitized, the wasp larvae often fail to develop, thanks to the action of the bacteria.
   • Pea Aphids (Acyrthosiphon pisum): Another example involves Spiroplasma infection in pea aphids. These aphids, when harboring Spiroplasma or other defensive symbionts like Hamiltonella defensa, show increased resistance to parasitoid wasps like Aphidius ervi. The symbiotic bacteria reduce the success rate of parasitoid development, helping the aphid survive the attack.
4. Symbiosis Costs and Benefits:
   • Benefit: The primary benefit of Spiroplasma infection for hosts like Drosophila or aphids is the increased survival rate against parasitoid wasp attacks, which can be a significant evolutionary advantage in environments where parasitoids are prevalent.
   • Cost: However, carrying Spiroplasma can come with metabolic costs. The bacteria may reduce the host's overall fitness in environments where parasitoid pressure is low, as resources are diverted toward maintaining the symbiosis. In the absence of parasitoid wasps, infected insects might have slower growth rates or reduced reproductive success.
5. Evolutionary Implications:
   The presence of Spiroplasma and other symbiotic bacteria in insects represents an example of evolutionary arms races between hosts, parasitoid wasps, and symbionts. As parasitoid wasps develop strategies to overcome the defenses of their hosts, hosts in turn acquire or maintain symbiotic relationships with bacteria that offer protection. This continuous co-evolution shapes the dynamics of parasitism and survival in natural ecosystems.

Conclusion

In the context of parasitoid wasps, Spiroplasma plays a fascinating role as a defensive ally for some insects. By providing protection against the development of wasp larvae inside their hosts, Spiroplasma helps insects survive parasitoid attacks, demonstrating the complex interactions between hosts, parasites, and symbiotic bacteria in nature. This defensive symbiosis showcases a powerful strategy of biological warfare within the insect world.

So, Spiroplasma is an example of the ludicrously complex, Heath-Robinson process that the mindless evolutionary process can produce but which would embarrass any intelligent designer who invented it.

Firstly, this supposed designer designs parasitoid wasps to lay their eggs in insect hosts, then it regards this as a problem in need of a solution, so, rather than stopping the parasitoid wasp parasitizing the insects, it gives the insects the ability to prevent the eggs developing inside its body, but, rather than giving the insects genes to produce the required toxins, it gives that ability to a bacterium and infects the insect with it.

So, the potential victim of the parasitoid wasp the designer designed to victimise it, needs to host a bacterium so it can resist being parasitised and, where there are few parasitoid wasps, the bacterium has to be fed and so exacts a toll on the insect it was designed to protect.

Creationists regard complex systems such as this as evidence of a single, super-intelligent designer - a conclusion that probably tells us more about creationists than they might wish us to know.
So, with that digression out of the way, here are the technical details of the newly-discovered parasitoid wasp:

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Abstract
Parasitoid wasps are exceptionally diverse and use specialized adaptations capable of manipulating the physiology and behaviour of host organisms¹. In more than two centuries since the first records of Drosophila-parasitizing wasps, nearly 200 described and provisional parasitoid species of drosophilids have been identified². These include endoparasitoids and ectoparasitoids, as well as species attacking larval and pupal hosts³. Despite a deep history of research attention and remarkable biodiversity, a wasp species that attacks and develops inside the adult stage of a fly host has not been described previously. Here we report the discovery of a wasp species that infects the adult stage of fruit flies in the genus Drosophila, including one of the most deeply studied model organisms in biology, Drosophila melanogaster. Notably, this wasp can be easily collected from backyard fly baits and has a broad geographic distribution throughout the eastern USA. We document its life history and unique host interactions, including egg-laying into and larval emergence from adult flies, and provide protocols to raise wasps from wild-caught host flies. Our results emphasize the need for ongoing research investment in insect biodiversity and systematics. As parasitoid research continues to uncover unusual biology and supports fundamental mechanistic insights into immunity⁴, metabolism⁵, ecology⁶, evolution^7,8,9 and behaviour^10,11,12, we anticipate that this wasp’s association with the laboratory model organism, D. melanogaster, will provide new research opportunities across the life sciences.

Main
Evolutionary conflict between parasites and hosts is a driving force behind some of the most specialized adaptations observed across the tree of life^13,14,15. Among the insects, such adaptations are used by the parasitoid wasps, which lay their eggs and develop in or on a live host. In this paper we describe a wasp species that parasitizes the adult stage of Drosophila flies—a parasitoid–host relationship that has not been described previously. Research on the natural parasites of the model fruit fly Drosophila has been ongoing since the early nineteenth century. In more than two centuries since the first records of Drosophila-parasitizing wasps (for example, Tanycarpa bicolor (Nees 1814)), nearly 200 described and provisional species of parasitoids of drosophilids have been identified². These include figitid and braconid wasps, which lay their eggs within fly larvae, and pteromalid, diapriid and encyrtid wasps, which attack host pupae³. Despite this deep history and rich phylogenetic diversity, a wasp species that attacks and develops inside the adult stage of Drosophila or any other fly has not been reported previously.

Parasitoid wasps of adult insects
Parasitoids of adults (imagobionts) are known to attack other orders of holometabolous insects. Members of some genera of the braconid wasp subfamily Euphorinae attack coleopteran, hymenopteran and neuropteran adults^16,17,18,19. Other euphorines use larval coleopterans, lepidopterans and raphidiopterans²⁰ as well as nymph and adult stages of several paurometabolous insects including psocopterans, orthopterans and hemipterans^16,17. Outside Euphorinae, imagobiosis is rare²¹. This may be due to increased mobility of potential hosts, thickness of the chitinous exoskeleton and development of defensive responses not available to all juvenile stages (for example, kicking appendages, powerful mandibles and potent chemicals)²¹. Even so, imagobionts have thrived in this unique niche, as evidenced by the effectiveness with which they parasitize and manipulate host biology and the peculiar mechanisms sometimes involved. For example, an RNA virus and potentially other venom components of the euphorine Dinocampus coccinellae paralyse adult spotted lady beetles to elicit a cocoon-guarding behaviour following larval emergence from the host body¹¹.

The subfamily Euphorinae is also characterized by repeated host shifts across major insect orders. It is among the most successful subfamilies in the family Braconidae with regard to species diversity and host range—the subfamily is composed of 54 unique genera with a host range spanning 8 insect orders, before this study^16,17,19,20. Despite these elements of striking diversity, frequent host shifts and remarkable solutions to the unique challenges of imagobiosis, many aspects of euphorine wasp biology remain understudied, perhaps owing in part to challenges in laboratory rearing and missing host records for many species collected as adults.

Here we report a previously undescribed euphorine parasitoid wasp belonging to the genus Syntretus in the hymenopteran-parasitizing tribe Syntretini. Although Syntretus species have long been known to occur in North America^22,23, their hosts have remained undescribed. In the Old World, the hosts of just four syntretines have been described^24,25,26,27. As these are all hymenopteran hosts, it was widely assumed that Hymenoptera is the sole host order for this tribe; however, the most recent revision for European Syntretus emphasized the paucity of biological information regarding species in this genus²⁸. The wasp species naturally infects the adult stage of several divergent host species in the genus Drosophila across the eastern USA, including Drosophila affinis and D. melanogaster, an unexpected host order record both for the genus Syntretus and the subfamily Euphorinae as a whole. We show that flies infected with this wasp are easily collected from fruit fly baits in both rural and suburban backyards in Mississippi, Alabama and North Carolina. We also present protocols to rear adult wasps from wild-caught host flies, and we document their life history and host interactions with photographs and video. Overall, this discovery creates new avenues of research with both euphorines and Drosophila and presents unexpected new biology and ecology in a highly studied model organism.

Fig. 1: Adult Drosophila are parasitized by a previously undescribed species in the euphorine genus Syntretus.

A phylogram constructed from concatenated nuclear and mitochondrial gene sequences of select euphorine wasps (left), with images and descriptions of the host species (right). Nuclear loci are genes encoding carbamoylphosphate synthase domain protein (CAD), 18S rRNA and 28S rRNA. The mitochondrial locus is COI. Members of the sister taxa Cenocoelius and Asiacentistes are included as outgroups. The gene sequences of S. perlmani group with high support inside the genus Syntretus. Branches with Shimodaira–Hasegawa-like maximum likelihood support values ≥ 0.9 are labelled with a circle. Taxon labels are coloured by host order. GenBank sequence accession numbers are listed in the Supplementary Data. Host insect photographs are adapted with permission as follows (top to bottom, excluding the fruit fly): cerambycid larva, Gilles San Martin under a CC BY 2.0 licence; Nezara viridula, Bugwood.org, Robert and Lesley Ingram under a CC BY 3.0 licence; Pityogenes chalcographis, Gilles San Martin under a CC BY 2.0 licence licence; Formica sp., Bugwood.org, Joseph Berger under a CC BY 3.0 licence; Apis mellifera, Bugwood.org, David Cappaert under a CC BY 3.0 licence; T. carbonaria, Alison Bockoven; Disonycha triangularis, Bugwood.org, Joseph Berger under a CC BY 3.0 licence; Coleomegilla maculata, Bugwood.org, Whitney Cranshaw under a CC BY 3.0 licence; Helicoverpa armigera, Bugwood.org, Gyorgy Csoska under a CC BY 3.0 licence; Formica obscuriventris, Gary Alpert; Acalymma vittatum, Bugwood.org, G. J. Holmes under a CC BY 3.0 licence.

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Fig. 2: Life stages of S. perlmani.

a,b, The development of wasp larvae inside host flies (a) is accompanied by growth of wasp teratocytes (b, black arrows), which can be seen through the host abdominal cuticle and obstruct the view of the testes (b, white arrow). c, The second and following larval instars lack a head capsule and tail spike, and the final instar grows to nearly the length of the host fly (see Supplementary Video 2). d, Pupal development takes place within a white silken cocoon as is typical of euphorine wasps. e, Larval emergence is always from the abdomen and has been observed to occur between the second and third tergites (dorsolaterally) or laterally through a tear in the abdominal cuticle. f, The adult wasp (male shown) is small, yellowish brown and approximately 1.5 mm in length. Scale bars, 0.5 mm (a–d) and 1 mm (e,f).

Moore, L.D., Chris Amuwa, T., Shaw, S.R. et al.
Drosophila are hosts to the first described parasitoid wasp of adult flies.
Nature (2024). https://doi.org/10.1038/s41586-024-07919-7

Copyright: © 2024 The authors.
Published by Springer Nature Ltd. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

Creationists traditionally abandon the pretense that creationism is a science and resort to religious superstition to explain parasites as somehow the fault of humans with 'The Fall', which caused genetic entropy and 'devolution' from an initial created perfection (© Micheal J Behe/Deception Institute), but that of course is nonsensical as well as being unscientific because any genetic changes that make the parasite more successful are beneficial evolutionary changes that can't rationally be described as less perfect than their predecessors.

So, to cling to the 'intelligent [sic] design' notion, creationists have to accept that the intention of creating these parasitoid wasps was to make their victims suffer, since that is undoubtedly what they do - which mean the designer was not only malevolent but inventively and calculatingly so.

And, even if creationists perform the required mental gymnastics to cling on to the absurd superstition that these parasites were the result of 'sin', there would have been no reason for Noah to keep them alive on the Ark, so God could have simply wiped the Earth clean of these things had it so chosen, but according to creationist mythology, it chose not to; instead it chose to preserve them while it committed global genocide.

Or at least that seems to be what creationists would prefer us to think their beloved creator god di, rather than accept the evidence-based explanation of mindless, evolution by natural processes operating without a plan or objective.

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