Alternative host-searching strategy reported for the ant parasitoid wasp Ghilaromma orientalis

“In our ten years of frantic observation, we were fortunate enough to observe the parasitic behavior of G. orientalis a single time.”

Guest blog post by Yu Hisasue, Kazuhiko Konishi, and Kenji Takashino

Parasitoid wasps have developed behaviors to adapt to the ecology of various hosts and overcome their means of avoiding parasitism. Host searching behavior is a crucial stage for parasitoids, not only for efficient host search, but also for competing with other parasitoids that exploit the same host as a resource. A variety of such behaviors has been reported, including utilizing chemical or sonic cues. Parasitoid wasps select their strategies based on their own morphology, their host, and the host’s habitat.

Parasitoid wasps that challenge the ant society are known to have highly specialized morphologies and behaviors.

Female of Ghilaromma orientalis hanging from the grass above the ant trail with her head facing the trail.

All members of the subfamily Hybrizontinae are ant parasitoids, and specialize to the ant society, representing the third most diverse group of ant parasitoid wasps after Eucharitidae and Neoneurini. The oviposition behavior has been reported for three species belonging to three different genera in Hybrizontinae: Ogkosoma cremieri, Neohybrizon mutus, and Hybrizon buccatus. In these species, the females hover over an ant trail, and when they come across ant larvae carried by workers, they attack and lay eggs on the ant larvae.

No reports have been made for oviposition behavior in the genus Ghilaromma. G. orientalis was suggested to be a specialist of Lasius nipponensis, but its oviposition behavior was unknown.

Female Ghilaromma orientalis using her front legs to contact an ant larva and directing her abdomen towards it, while maintaining a firm grip on the grass with her hind legs.

In our ten years of frantic observation, we were fortunate enough to observe the parasitic behavior of G. orientalis a single time. On 20 October 2015, Kenji Takashino observed the oviposition and took pictures of it on his phone.

He noticed that the female, hung on the grass growing along the ants’ trail on its hind legs with its head down, and when workers with larvae pass by, stretched its abdomen toward the larvae with its hind legs remaining on the grass.

We published these first observations of the oviposition behavior of G. orientalis in a research article in the Journal of Hymenoptera Research.

Female Ghilaromma orientalis maintaining a firm grip on the grass with her hind legs while adjusting her body position to oviposition onto a larva being carried away by an ant.

There are different merits and demerits of the two strategies in Hybrizontinae. The active type has the advantage of covering a wider search area and enabling the movement of the parasitoid to areas where the ants carrying larvae are located. However, this strategy has the drawback that hovering of parasitoid wasps over an ant trail alerts the ants and prevents larva-carrying ants from exiting the nest entrance or covered area. In addition, ants have been observed to open their mandibles to threaten hovering wasps, which then occasionally fail to fly or get captured by worker ants.

Workers of Lasius nipponensis with their mandibles open, alerted to the hovering Ogkosoma cremieri.

The ambush type has the limitation of a narrow search area. As ant larvae are not always conveniently transported by workers close to the wasp, narrowing the search area directly leads to a decrease in parasitic opportunities. However, the ambush type strategy affords G. orientalis the advantage of laying eggs without being noticed by ants and in a narrow environment where wasps cannot fly in active type.

In addition, we report a new host ant (Lasius cf. fuliginosus) for G. orientalis. Some members of this species group are known to transport their larvae outside the nest. Therefore, it is plausible that G. orientalis may use not only a single ant species, but multiple L. fuliginosus-group species that have a habit of transporting larvae outside the nest.

Although we made only one observation of the wasp, we compared and discussed the other ecological information and parasitic behavior of closely related species using observations, literature, and studies on the parasitic behavior of other well-studied parasitoid wasps.

Research article:

Hisasue Y, Konishi K, Takashino K (2023) An alternative host searching strategy found in the subfamily Hybrizontinae (Hymenoptera, Ichneumonidae). Journal of Hymenoptera Research 96: 629-639. https://doi.org/10.3897/jhr.96.106836

A double defensive mutualism? A case between plants, extrafloral nectaries, and trophobionts

Тhis is the first case reported in the literature of a double defensive mutualism occurring simultaneously on a single plant species.

Guest blog post by Cássio Pereira

The Zeyheria montana shrub is quite common in the Brazilian Cerrado and is known to have extrafloral nectaries on the leaf blade that attract patrolling ants such as the aggressive Ectatomma tuberculatum. The ant, in turn, defends the leaves against the action of herbivores. However, extrafloral nectaries can distract ants on the leaves, segregating them from the reproductive parts and preventing them from driving away pollinators, which can benefit the action of florivores and nectar robbers.

Surprisingly, in southeastern Brazil, we observed a second defensive mutualism occurring on the reproductive tissues of these shrubs between E. tuberculatum and the treehopper Guayaquila xiphias, which provides the ant with honeydew in exchange for protection. This trophobiosis relationship (interaction between ants and phytophagous hemipterans that secrete sugary exudates) seems to be effective not only in the defense of floral buds and flowers, but also of the fruit, which, despite being dry, contains a lot of water in its formation and is attacked by beetles of the Curculionidae family.

The treehoppers G. xiphias at the base of Z. montana fruits.

As far as we know, this is the first case reported in the literature of a double defensive mutualism occurring simultaneously on a single plant species. Given this record, important questions arise regarding these interactions. Is the trophobiosis that occurs in reproductive organs capable of increasing the fitness of these plants? Although these ants are probably also scaring away possible pollinating insects, could the fact that Z. montana is primarily pollinated by hummingbirds offset this loss given that hummingbirds are larger and perhaps immune to ant attacks?

Our record raises more questions than it answers. Long-term Z. montana population studies would help improve our ecological understanding of these interactions.

Accidental tree wound reveals novel symbiotic behavior

Despite significant movement restrictions during the first wave of the pandemic in Panama City, a group of curious high school students roamed their neighborhood drilling holes into Cecropia trees and documenting how Azteca alfari ants responded to damage to their host plant.

During the pandemic, five curious high school students accidentally discovered how Azteca alfari ants respond to damage to their Cecropia host trees. Photo by Donna Conlon

One afternoon, during the early days of the COVID-19 pandemic in Panama, a bored teenager with a slingshot and a clay ball accidentally shot entry and exit holes in a Cecropia tree trunk. These are “ant-plant” trees, which famously cooperate with fierce Azteca ants; the trees provide shelter and food to the ants, and in exchange the ants defend their leaves against herbivores. The next morning, to his surprise, the Azteca alfari ants living within the Cecropia trunk had patched up the wound.

This unexpected occurrence drove five curious high school students, with time on their hands, to participate in the Smithsonian Tropical Research Institute’s (STRI) volunteer program, and they enlisted STRI scientist William T. Wcislo’s help in devising their experiment. Despite significant movement restrictions during the first wave of the pandemic, they roamed their neighborhood drilling holes into Cecropia trees and documenting the ants’ responses to the damage.

They found that as soon as the plants had holes drilled into them, the ants ran to the wound area and began patching it up. Within 2.5 hours, the size of the hole had been significantly reduced and it was often completely repaired within 24 hours.

Although some Azteca ants are known to defend their Cecropia host plants against herbivores, these new results, published in the Journal of Hymenoptera Research, reveal that not only do the ants behave in ways to minimize damage to their hosts, but when damage does occur, they actively work to fix it, particularly when their brood is directly threatened.

“I was totally surprised by the results,” says William Wcislo. “And I was impressed by how they developed a simple way to test the idea that ants repair damage to their home.” 

Azteca ant and Cecropia plant responses to wounds in the stems a a sealed hole after 24 hours, but not yet filled in to the stem surface (arrow) b a fully patched and filled-in hole after 24 hrs, oozing sap from the ant-sealed wound (arrow) c a natural plant scar surrounding a 6.4 mm hole that was fully sealed by the ants, approximately 5 months later d a hole in a plant without ants after 24 hrs, showing the green wall of the opposite side of the stem (arrow).

Sloths and silky anteaters often visit Cecropia trees and their sharp toenails sometimes pierce the wood, so the researchers speculate that these occurrences, which are far more common and ancient threats to the Cecropia than teenagers shooting clay balls at them, could have led Azteca alfari ants to evolve the observed repair behavior when their host plant is damaged. 

Their experiment also left them with new questions, since not all of the ant colonies repaired the damage to their host plants. Understanding what factors influence the ants to take action could be the subject of future research for these budding scientists, although perhaps to be addressed after graduating from high school.

“Sometimes messing around with a slingshot has a good outcome,” said lead author Alex Wcislo. “This project allowed us to experience first-hand all the intricacies behind a scientific study. All in all, it was a great learning experience, especially considering the difficulties associated with fulfilling this due to COVID-19.”

Research article:

Wcislo A, Graham X, Stevens S, Toppe JE, Wcislo L, Wcislo WT (2021) Azteca ants repair damage to their Cecropia host plants. Journal of Hymenoptera Research 88: 61-70. https://doi.org/10.3897/jhr.88.75855

The ants, bees and wasps of Canada, Alaska and Greenland – a checklist of 9250 species

Knowing what species live in which parts of the world is critical to many fields of study, such as conservation biology and environmental monitoring. This is also how we can identify present or potential invasive and non-native pest species. Furthermore, summarizing what species are known to inhabit a given area is essential for the discovery of new species that have not yet been known to science.

American Pelecinid Wasp (Pelecinus polyturator) from Driftwood Provincial Park, Ontario, Canada. Photo by Henri Goulet

For less well-studied groups and regions, distributional species checklists are often not  available. Therefore, a series of such checklists is being published in the open-access, peer-reviewed Journal of Hymenoptera Research, in order to address the issue for a group of organisms that, despite its size and diversity, is still poorly known: the insect order Hymenoptera, which includes ants, bees and wasps. The surveyed area spreads across northern North America, which comprises Canada, Alaska (U.S.) and Greenland (Denmark), and occupies about 9.3% of the world’s total land mass.

The last distributional survey of Hymenoptera in North America was published in 1979, where about 6000 described species were recorded from Canada and 600 from Alaska. The current survey lists 8933 species in Canada and 1513 in Alaska, marking an increase of 49% and 152%, respectively. A total of 9250 described species are recorded from northern North America. Considering that there are approximately 154,000 described species of Hymenoptera, northern North America has about 6% of the current world total. 

A cuckoo wasp of the genus Hedychridium from Manitoulin Island, Ontario, Canada. Photo by Henri Goulet

Highlights of the series will include updated distributions of over 900 species of bees, which will provide valuable insight into native pollinators at a time when honey bees are in decline. Nearly 230 species of ants and over 100 species of vespid wasps (hornets and yellow jackets) are recorded, including pest species such as the widespread pharaoh ant and the newly invasive Asian giant hornet in British Columbia.

Pigeon tremex (Tremex columba) from Manitou Lake, Manitoulin Island, Ontario, Canada. Photo by Henri Goulet

By far, the majority of species of Hymenoptera found in northern North America and the world are parasitoids, which develop on or in other invertebrate hosts and are therefore of great interest to the biological control of pests. Of the 9250 species recorded, more than three-quarters (over 7150 species) are parasitoids. These distributional lists provide essential baseline information required prior to undertaking studies to introduce biological control agents of invasive pests that may have escaped their native, natural enemies when they arrived in North America.

Megarhyssa macrura from Ottawa, Ontario, Canada. Photo by Henri Goulet

The topical collection “Checklists of the Hymenoptera of Canada, Alaska and Greenland” is to contain a total of eleven papers, where the introduction and the first two checklists: of sawflies (758 species) and one of the groups of “microhymenoptera” (the chalcidoid parasitic wasps) (1246 species) have just been published.The other checklists are to follow over the next several years. The associated data are also being uploaded to the Global Biodiversity Information Facility (GBIF), allowing for periodic updates over time.

When complete, this will be the largest species checklist for any group of organisms in northern North America. Considering that it is estimated that we currently have documented less than half of the species of Hymenoptera present in northern North America, there is still a great amount of work to do on this fascinating group of insects.

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Original sources:

Bennett AMR (2021a) Checklists of the Hymenoptera of Canada, Alaska and Greenland – Introduction. Journal of Hymenoptera Research 82: 1-19. https://doi.org/10.3897/jhr.82.60054

Bennett AMR (2021b) Checklist of the Hymenoptera of Canada, Alaska and Greenland. Agriculture and Agri-Food Canada. Checklist dataset https://doi.org/10.5886/4piso5 [accessed via GBIF.org: 12 March 2021].

Goulet H, Bennett AMR (2021) Checklist of the sawflies (Hymenoptera) of Canada, Alaska and Greenland. Journal of Hymenoptera Research 82: 21-67. https://doi.org/10.3897/jhr.82.60057

Huber JT, Bennett AMR, Gibson GAP, Zhang YM, Darling DC (2021) Checklist of Chalcidoidea and Mymarommatoidea (Hymenoptera) of Canada, Alaska and Greenland. Journal of Hymenoptera Research 82: 69-138. https://doi.org/10.3897/jhr.82.60058

New ant species named in recognition of gender diversity

A newly discovered miniature trap jaw ant from the evergreen tropical forests of Ecuador bears the curious Latin name Strumigenys ayersthey, among hundreds, which are also named in honour of people, but end with -ae (after females) and –i (after males). This makes the newly described ant perhaps the only species in the world to have a scientific name with the suffix –they, thus celebrating gender diversity.

A view of the head of Strumigenys ayersthey

The insect was first found by Philipp Hoenle of the Technical University of Darmstadt, Germany, during a cooperative investigation of the Reserva Río Canandé in 2018. The reserve belongs to the NGO Jocotoco, and preserves a small part of the highly threatened biodiversity hotspots called the Chocó.

Hoenle reached out to taxonomic expert Douglas Booher of Yale University. Soon, Booher responded with excitement that this species was unlike any other of the 850+ species belonging to its genus. As a result, the team described the previously unknown to science species and its remarkable trap-jaw morphology in a research paper, published in the peer-reviewed, open-access journal ZooKeys.

Curiously, it was no other but lead singer and lyricist of the American alternative rock band R.E.M. Michael Stipe that joined Booher in the writing of the etymology section for the research article. This is the part in the publication, where they honor their mutual friend, activist and artist Jeremy Ayers and explain the origin of the species name.

“In contrast to the traditional naming practices that identify individuals as one of two distinct genders, we have chosen a non-Latinized portmanteau honoring the artist Jeremy Ayers and representing people that do not identify with conventional binary gender assignments – Strumigenys ayersthey”. The ‘they’ recognizes non-binary gender identifiers in order to reflect recent evolution in English pronoun use – ‘they, them, their’ and address a more inclusive and expansive understanding of gender identification.”

A side view of Strumigenys ayersthey

Current nomenclature practice on how to name animal species after people only differentiates between male and female personal names, offering respectively the ending -ae for a woman or -i for a man.

The research team additionally propose that the -they suffix can be used for singular honorific names of non-binary identifiers.

A micro-CT scan of Strumigenys ayersthey

When asked about the choice of a name for the ant, Booher said: “Such a beautiful and rare animal was just the species to celebrate both biological and human diversity. Small changes in language have had a large impact on culture. Language is dynamic and so should be the change in naming species – a basic language of science”. 

With their choice, the team invites the scientific community to keep pace with the likes of Oxford English Dictionary, Merriam-Webster Unabridged Dictionary and HSBC Bank, who have also adapted their own institutional practices, language usage and recognition to represent gender diversity.

“The discovery of such an unusual rare ant highlights the importance of scientific exploration and conservation of the Chocó region in Ecuador, which is at the same time one of the most biodiverse and threatened areas on our planet.”

the researchers add in conclusion.

Strumigenys ayersthey can be distinguished by its predominantly smooth and shining cuticle surface and long trap-jaw mandibles, which make it unique among nearly a thousand species of its genus. The researchers haven’t been able to obtain more specimens of the species, which suggests that it’s rare. 

Original source:

Booher DB, Hoenle PO (2021) A new species group of Strumigenys (Hymenoptera, Formicidae) from Ecuador, with a description of its mandible morphology. ZooKeys 1036: 1–19. https://doi.org/10.3897/zookeys.1036.62034

New ant species from Borneo explodes to defend its colony

Minor worker of the new species in a defensive pose.
Minor worker of the new species in a defensive pose.

Amongst the countless fascinating plants and animals inhabiting the tropical rainforests of Southeast Asia, there are the spectacular “exploding ants”, a group of arboreal, canopy dwelling ants nicknamed for their unique defensive behaviour.

When threatened by other insects, minor workers can actively rupture their body wall. Apart from leading to the ants’ imminent death, the “explosion” releases a sticky, toxic liquid from their enlarged glands, in order to either kill or hold off the enemy.

Three 'exploding' ants of the new species grasping onto a weaver ant.
Three ‘exploding’ ants of the new species grasping onto a weaver ant.

Curiously enough, while these ants’ peculiar behaviour was first mentioned in distant 1916, no new species have been formally described since 1935, due to insufficient evidence. Instead, scientists used to simply refer to them as the members of a remarkable species group – Colobopsis cylindrica, better known as “the exploding ants”.

That was until an interdisciplinary research team from Austria, Thailand and Brunei came together led by their shared fascination with these insects and their extraordinary mechanism of self-sacrifice (also called autothysis) in 2014. Thus, entomologists, botanists, microbiologists, and chemists from the Natural History Museum ViennaTechnical University ViennaIFA Tulln and Universiti Brunei Darussalam together identified roughly 15 separate species of exploding ants, with one of them now described as new to science in the open access journal ZooKeys.

Aptly named Colobopsis explodens, previously nicknamed “Yellow Goo” for its bright yellow gland secretion, the new species has been picked as the model species of the group, after the scientists deemed it to be “particularly prone to self-sacrifice when threatened by enemy arthropods, as well as intruding researchers”.

The new species grasping onto a larger unidentified 'exploding' ant.
The new species grasping onto a larger unidentified ‘exploding’ ant.

Being a “model species” means that the ant will serve as an important navigation point in future studies on exploding ants. Publications regarding their behaviour, chemical profile, microbiology, anatomy and evolution are currently in preparation, say the authors. In addition, there are several more new species expected to be described in the near future.

While minor workers exhibit the ability to “explode”, the other castes have specialities of their own. For example, major workers (also called “doorkeepers”) have big, plug-shaped heads used to physically barricade the nest entrances against intruders.

Major worker of the new species ('doorkeeper') with characteristically enlarged head.
Major worker of the new species (‘doorkeeper’) with characteristically enlarged head.

During a sampling trip to Brunei in 2015, project members Alexey Kopchinskiy and Alice Laciny even managed to observe queens and males on a mating flight. They sampled the first males of these ants ever to be seen.

The same expedition was used to record the ants’ activity schedule and conduct the first experiments on food preferences and exploding behaviour.

While the exploding ants play a dominant role in rainforests, their biology still holds a number of secrets. The observations and experiments conducted on the newly described species have laid important groundwork for future research that will uncover even more details about these enigmatic explosive insects.

Watch this video to observe the behaviour of the exploding ants in various settings.

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Learn more about the ‘Exploding ants’ project at: http://explodingants.com/

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Original source:

Laciny A, Zettel H, Kopchinskiy A, Pretzer C, Pal A, Salim KA, Rahimi MJ, Hoenigsberger M, Lim L, Jaitrong W, Druzhinina IS (2018) Colobopsis explodens sp. n., model species for studies on “exploding ants” (Hymenoptera, Formicidae), with biological notes and first illustrations of males of the Colobopsis cylindrica group. ZooKeys 751: 1-40. https://doi.org/10.3897/zookeys.751.22661

 

Heat-loving Australian ants believe in diversity, hint 74 species new to science

The ‘furnace ants’ or ‘honeypot ants’ present a very large genus of ants, Melophorus, confined to Australia. Long believed to be megadiverse, some scientists have even suggested that the group may contain ‘well over 1000 species’. However, to this point, only 32 species and subspecies had been described.

Scientists Dr Brian Heterick of Curtin UniversityDr Mark Castalanelli of Ecodiagnostics Pty Ltd and Dr Steve Shattuck of the Australian National University, funded by an internationally competitive Australian Biological Resources (ABRS) grant, set out to find the true facts.

As a result, they discovered as many as 74 new species belonging to Melophorus. In their study, published in the open access journal ZooKeys, they also provide a taxonomic key to the workers of a total of 93 species in the genus.

Among the studied ants, there are quite bizarre ones, including a species (Melophorus hirsutus) whose eyes are strangely protruding out of his head to a varying degree. In the extreme cases, the eyes are so pointy that could be likened to ice-cream cones. Named many years ago, this ant appears to be older than the rest of the examined living species. Furthermore, unlike most of them, it does not seem adapted to heat. It is confined to the wet eastern coast of Australia.

Dr Heterick spent two weeks collecting specimens in the often rugged and forbidding terrain of Western Australia, while the team also asked a number of major museum collections to loan them specimens.

The newly collected ants were placed in alcohol and subjected to genetic tests using one mitochondrial and four nuclear genes. The findings were then compared with those from physical examinations to prepare the taxonomic key – a set of distinctive features per species that can be used to differentiate within the group.

Given the generally complex nature of these ants, the authors expect for the genus to further expand in future. They speculate that even though the numbers may increase to around 100 species, not the ‘well over 1000’ previously predicted, they still illustrate an incredible diversity.

The authors estimate that Melophorus arose around 35 million years ago. The closest relatives of the genus are also confined to the Australasian region with the exception of a single genus living in South America.

Furthermore, the genus is also quite astonishing thanks to another trait shared among the species.

“By the way, this group of ants has a thing or two to tell those of us who get lost easily!” comments lead author Dr Brian Heterick.

“They can find their way home in a featureless landscape by means of an internal compass influenced by information gathered on earlier journeys. We are not the first species to use a computing system!”

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Original source:

Heterick B, Castalanelli M, Shattuck S (2017) Revision of the ant genus Melophorus (Hymenoptera, Formicidae). ZooKeys 700: 1-420. https://doi.org/10.3897/zookeys.700.11784

The Radiohead ant: A new species of ‘silky’ ant grows fungus gardens for food

The ants of the genus Sericomyrmex – literally translated as ‘silky ants’ – belong to the fungus-farming ants, a group of ants that have figured out how to farm their own food. The silky ants are the less well-known relatives of the famous leaf-cutter ants – well-studied, photogenic model organisms that you simply cannot avoid if you take a trip to the Neotropics.

For their study, now published in ZooKeys, Ana Ješovnik and Ted R. Schultz from the Smithsonian Institution‘s Ant Lab in Washington, D.C., collected silky ants from across their entire range in Central and South America, and revised the genus based on DNA sequence data and morphology. In the end, they turned out to have discovered three new species.

One of those species, Sericomyrmex radioheadi, collected in the Venezuelan Amazon, was named after the famous British music band Radiohead.

Image3“We wanted to honor their music” one of the authors, Ana Ješovnik, says. “But more importantly, we wanted to acknowledge the conservation efforts of the band members, especially in raising climate-change awareness. ”

Using a scanning electron microscope, the authors found that the bodies of the ants are covered with a white, crystal-like layer. Curiously, this previously unknown layer is present in female ants (both workers and queens), but is entirely absent in males. Both the chemical composition and the function of this layer are unclear.

One possibility is that the layer is microbial in origin and that it has a role in protecting the ants and their gardens from parasites. This is interesting, because most of the fungus-farming ants cultivate antibiotic-producing bacteria on their bodies to protect their gardens from microbial weeds. In the meantime, in Sericomyrmex these bacteria are absent, yet their gardens are also parasite-free. Figuring out if this crystal-like layer has a role in protecting these ants’ fungus gardens might provide clues for managing diseases in human agriculture and medicine.

At only four million years, Sericomyrmex is an evolutionary youngster, the most recently evolved genus of fungus-farming ants, and an example of rapid radiation – comparable to other fast-evolving groups, such as the freshwater fishes in Africa, or the Hawaiian fruit flies.

Rapid radiation is a process in which organisms diversify quickly into a multitude of forms, making these ants good candidates for studies into speciation and evolution. In the present article, the authors acknowledge that some of the species they describe might, in fact, be multiple species that look alike, but because the ants are in the early stages of speciation, this is hard to detect.

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Original source:

Ješovnik A, Schultz TR (2017) Revision of the fungus-farming ant genus Sericomyrmex Mayr(Hymenoptera, Formicidae, Myrmicinae). ZooKeys 670: 1-109. https://doi.org/10.3897/zookeys.670.11839

Rarely-seen event of ant brood parasitism by scuttle flies video-documented

While many species of scuttle flies are associated with ants, their specific interactions with their hosts are largely unknown. Brood parasitism (attacking the immature stages, rather than the adult ants), for example, is an extremely rarely observed and little-studied phenomenon. However, a research team from the USA and Brazil, led by Dr. Brian Brown, Natural History Museum of Los Angeles County, have recently video-documented two such occasions. The observations are published in the open access Biodiversity Data Journal.

One of the videos, taken in Brazil, shows female scuttle flies attacking ants evacuating their nest. Having had their colony exposed, worker ants try to carry the brood to the nearest shelter. The flies follow these workers on foot, and bump into them in attempt to make them drop the larvae. The scientists have provided a video of an ant which, when harassed, left a larva in a partially exposed position and fled. Immediately, the fly attacked the larva, laying an egg inside its body. The fact that the flies attack the relatively soft-bodied larvae explains the puzzling structure of the ovipositor (egg-layer) of this species (Ceratoconus setipennis), which appears much less hardened than the ovipositor of species attacking adult ants. As a result of the present observation, however, their association with ants is no longer a mystery.

The second footage, filmed in Costa Rica, shows an undescribed species of scuttle fly (genus Apocephalus) that fly above the ants. When they spot a worker carrying brood, it would plunge down to it, approach the ant from behind and land on the (in this case) pupa. Then, it flips over onto its back, keeping the pupa between itself and the ant, while it lays an egg into the pupa from an upside-down position.

“The video documentation of two very different types of brood parasitism of ant species by scuttle flies was recorded in two countries within just a few months of one another,” conclude the authors. “This hints at the many remarkable behaviors of phorid flies that may still await discovery by the patient observer. It appears brood parasitism may not be as rare as was once assumed, and that there may be a tremendous amount of information to uncover about these behaviors.”

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Original source:

Brown B, Hash J, Hartop E, Porras W, Amorim D (2017) Baby Killers: Documentation and Evolution of Scuttle Fly (Diptera: Phoridae) Parasitism of Ant (Hymenoptera: Formicidae) Brood. Biodiversity Data Journal 5: e11277. https://doi.org/10.3897/BDJ.5.e11277

Flightless survivors: Incredible invertebrate diversity in Los Angeles metropolitan area

Urban wildlife is surprisingly understudied. We tend to know more about animals in exotic places than about those that live in our cities.

This is why researchers Emile Fiesler, president of Bioveyda Biological Inventories, Surveys, and Biodiversity Assessments, USA, and Tracy Drake, manager of the Madrona Marsh Preserve, looked into the fauna of the Madrona Marsh Preserve, California, a small nature preserve in one of the world’s largest metropolitan areas.

Consequently, they published the astonishing number of 689 species of invertebrates, which have managed to survive decades of farming and oil exploration, followed by development pressures, in the open access Biodiversity Data Journal. The study was minimally invasive as the live animals have been recorded with macro-photography.

Even though it is the insects that first developed the ability to fly, long before the dinosaurs became birds, the latter have always received the most of our attention. This major evolutionary breakthrough, which has occurred more than once in the past, is also a reason why insects are currently the most diverse animals on earth in terms of number of species.

“Insects and other invertebrates have filled all ecological niches and all corners of our planet,” explain the authors. “No surprise that these small creatures conquered our cities and invaded our homes as well.”

Most of the urban dwellers, however, have been introduced – accidentally or deliberately – by humans.

“The remainder – native ‘wild’ species – are able to survive in the city mainly due to their adaptivity,” they point out. “It is therefore surprising to find a number of flightless species in a small area surrounded by urbanization.”

The Madrona Marsh Preserve is located in Torrance, which is part of the Los Angeles metropolitan area. The greater Los Angeles Metropolitan area is one of the world’s largest, with a human population of more than 17 million.

Figure 2 = Bradynobaenid Wasp Fiesler-2016The Madrona Marsh Preserve, boasting seasonal wetlands, is well known as a birdwatchers’ paradise. Besides birds, its other vertebrates (mammals, reptiles, amphibians, and fishes), as well as its flowering plants, are relatively well known. The invertebrate fauna of the Preserve, on the other hand, aside from butterflies and dragonflies, was virtually unknown.

Interestingly, night surveys revealed the presence of a ‘second shift’ diversity, or creatures seemingly complementary to those active during the day.

Among the long-time survivors are wingless camel crickets as well as velvet ants, which are wasps whose flightless females look like furry ants. Another curiosity that intrigued the researchers is an obscure flightless female bradynobaenid wasp.

The researchers were especially surprised by their encounter with a large Solifugid [image 3] – also known as Camel Spider or Wind Scorpion. Solifugids are little-known arachnids that are neither spiders, nor scorpions, and can grow up to 15 cm (6 in). Their order’s name Solifugae translates from Latin as “those that flee from the sun”.Figure 3 = Solifugid Fiesler-2016

All in all, the biodiversity study resulted in 689 species without a backbone, belonging to 13 classes, 39 orders, and 222 families, found on this island surrounded by urbanization.

“Not unlike the moas and dodos, these ‘island’ inhabitants stayed grounded through the ages,” acknowledge the researchers.

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Original source:

Fiesler E, Drake T (2016) Macro-invertebrate Biodiversity of a Coastal Prairie with Vernal Pool Habitat. Biodiversity Data Journal 4: e6732. doi: 10.3897/BDJ.4.e6732

 

About the authors:

Emile Fiesler is president of Bioveyda Biodiversity Inventories, Surveys, and Studies, and Tracy Drake is manager of the Madrona Marsh Preserve.