Wednesday, August 31, 2022

Wasp Wednesday: Another Cricket Hunter, Lyroda subita

Crickets in the family Gryllidae are sufficiently diverse, and abundant enough, to be the target hosts for a variety of parasitoid wasps, especially those in the families Sphecidae and Crabronidae. There are previous posts about the Steel Blue Cricket Hunter, and the genus Liris, but here in eastern Kansas there is another player. Lyroda subita is easily confused with Liris, but the clue is in the "toes."

Like all of the larger cricket-hunting wasps, Lyroda is solitary, each female constructing her own nest, in this case an underground burrow. Whether she digs it herself is the subject of debate. At least some observations indicate the wasps use the abandoned burrows of other solitary wasps rather than excavating a nest themselves. The tunnel of Lyroda subita can be fifteen to thirty centimeters below the surface of the ground. There may be only one cell, or two. Historical records are rather scant.

The female hunts almost exclusively crickets of the family Gryllidae, both adults and immatures (nymphs). She subdues her quarry with a paralyzing sting in a nerve center that renders the victim limp. Transporting such a bulky insect is no problem for the agile wasp. She slings it beneath herself, grasps the cricket's antennae in her mandibles, and away she goes. She can run over the ground with it, but can also glide or even fly with it. Multiple crickets are used to provision a single cell, after which she lays an egg on the last cricket, seals the cell, and then repeats the entire process.

There is at least one record of L. subita using a different host: a pygmy mole cricket of the family Tridactylidae. Since these are mostly subterranean orthopterans, and not that closely related to crickets, the how and why of this anomaly remains unanswered. Other species of Lyroda from other parts of the world are known to use pygmy grasshoppers, family Tetrigidae, as hosts, and those insects occupy similar micro-habitats as pygmy mole crickets. Maybe it is a matter of what is available in a given habitat, then. Pygmy mole crickets and pygmy grasshoppers occur mostly in wet or damp situations along stream banks.

In our Leavenworth, Kansas yard, there are large numbers of Gryllus field crickets, and ground crickets of the subfamily Nemobiinae, offering Lyroda plenty of options.

L. subita is a medium-sized insect. Females range from 10-13 millimeters in body length, males slightly smaller at 6-10 millimeters. Both sexes are slate gray in color with silver highlights, especially on the abdomen. In the right light it can appear the abdomen is banded in dark gray and white. The ocelli, a trio of simple eyes on the crown of the head, between the compound eyes, are present. The most easily observed feature is on each "foot." The last tarsal segment bears a very large pad called an arolium (plural arolia), which differs markedly from the petite feet of the nearly identical Liris genus. Liris also has only a single mid-ocellus, the lateral simple eyes being reduced to longitudinal scars.

This species occurs throughout most of the United States (except for Washington, Oregon and the southwest states), southern Canada, the northern half of Mexico, and also Cuba and Hispaniola. There are twenty-one other species of Lyroda, most of which are found in southeast Asia, plus Africa, Australia, and South America.

Sources: Kurczewski, Frank E., and Margery G. Spofford. 1985. "A New Host Family for Lyroda subita (Hymenoptera: Sphecidae)," The Great Lakes Entomologist 18(3): 113-114.
Bohart, R.M. and A.S. Menke. 1976. Sphecid Wasps of the World: A Generic Revision. Berkeley: University of California Press. 695 pp.
Elliott, Lynette, et al. 2006. "Species Lyroda subita,"
Khvir, Viktor I., and Wojciech J. Pulawski. 2020. "A Revision of New World Lyroda Say, 1837 (Hymenoptera: Crabronidae)," Proceedings of the California Academy of Sciences Series 4, Volume 66, nol 13: 315-330.

Wednesday, August 17, 2022

Wasp Wednesday: Aulacids

Pristaulacus fasciatus female

Sometimes an unfortunate event yields something interesting later. More on that in a minute. Aulacid wasps are seldom seen, but also often overlooked due to their superficial resemblance to ichneumon wasps. They are found in similar situations as ichneumons, and behave similarly. Two genera and 185 species make up the family Aulacidae, and they collectively occur on all continents except Antarctica. There are thirty-two species in North America.

At 3 AM on June 1, 2022, a massive limb broke off of the Pin Oak tree in our front yard in Leavenworth, Kansas, USA. It apparently hit the ground before striking our house, but it did enough damage to require a new roof and gutters. Removal of the limb took place later that day, and I had the service that did the work leave the log sections in a pile around the base of the tree, where they sit currently. The least I could get out of this minor tragedy would be some interesting insects.

A female Chrysobothris sp. jewel beetle. Her larval offspring are potential hosts for aulacids.

Cut, living wood emits aromatic compounds that attract insects eager to exploit the resource. These include wood-boring beetles in the families Cerambycidae (longhorned beetles), and Buprestidae (jewel beetles or metallic wood-boring beetles) that lay their eggs in bark crevices. The beetle larvae that hatch then bore into the wood. In turn, the parasitoids of these beetles arrive. Aulacid wasps are known to be parasitoids of these beetles, especially the larvae of the longhorned beetles, as well as larval wood wasps in the family Xiphydriidae.

Another potential host for aulacids: Graphisurus fasciatus, a longhorned beetle.

I had collected aulacids in Cincinnati, Ohio when I lived there, and those specimens now reside with the rest of my collection at the Denver Museum of Nature and Science. I had not photographed any, except for one specimen of Pristaulacus rufitarsis in Colorado. I had the good fortune of getting permission to look for insects at a slash pile of freshly-cut pine in Black Forest, just north of Colorado Springs.

Pristaulacus rufitarsis female in Colorado, USA

Here in Kansas, on the western-most fringe of the eastern deciduous forest, I was not sure whether these wasps would occur here. I was delighted to finally spot a female of Pristaulacus fasciatus on the pile of logs in our front yard in late July. Since then, through mid-August, I have seen at least three specimens, and finally managed to get respectable images. All have been females. Perhaps mating takes place away from the logs and trees that the females scour for evidence of their intended hosts.

It has been interesting observing these wasps. They walk haltingly across the logs, bobbing their abdomens slightly, and slowly rowing their wings, which is enough to give one cause to think they might be stinging spider wasps. Indeed, Pristaulacus fasciatus may be part of a small mimicry ring, which I’ll address in a future post.

I notice that the female wasp probes every crack and crevice by inserting her antennae deeply into it, perhaps divining the location of a host that way. Once she locates a victim, she commences ovipositing. Grooves on the inner surface of her hind coxae (basal-most segments, connected directly to her thorax, help guide and stabilize her thin ovipositor as she inserts it.

Her ovipositor is entering the wood between her hind leg and middle leg.

Aulacids are identified by the attachment of the abdomen high on the thorax, a short “neck” behind the head, and a somewhat sinuous, not straight, ovipositor. The first two characters reveal the relationship of aulacids to ensign wasps and carrot wasps under the umbrella superfamily Evanoidea. Aulacus is the other genus, with species typically a bit smaller than Pristaulacus. Females of P. fasciatus have a body length averaging around 16 millimeters, while males are slightly smaller at 13 millimeters. They are conspicuous insects, easily spotted but only in these unusual situations.

Look for P. fasciatus from eastern Texas and Nebraska eastward, though it appears absent from most of the southeast U.S. and Canada. There is one record in New Mexico on iNaturalist.

Sources: Eaton, Eric R. 2021. Wasps: The Astonishing Diversity of a Misunderstood Insect. Princeton, NJ: Princeton University Press. 256 pp.
Smith, David R. 1996. “Aulacidae (Hymenoptera) in the Mid-Atlantic States, With a Key to Species of Eastern North America,” Proc. Entomol. Soc. Wash. 98(2): 274-291.

Tuesday, August 9, 2022

Why I am Reviewing The Trayvon Generation in a “Bug Blog”

I have been accused of being “political” even in some of the entomology posts in this blog, but there is nothing political about human rights. It is my opinion that there will be no abatement of the “insect apocalypse,” no permanent success in the conservation of endangered species of any kind, until we save our own species from racism and other forms of bigotry afflicting people of color, women, agender persons, the LGBTQ population, the disabled, the neurodivergent…..

The list of persecuted Homo sapiens continues to grow thanks to colonialism, patriarchy, white supremacy, religious extremism, extreme capitalism, ableism, and the inertia of assumptions. Because of this, what is inappropriate is to exclude discussions on these urgent matters from any forum, no matter how “off topic” it might appear at first glance. It is relevant to every facet of our lives, every profession, and every pursuit.

Elizabeth Alexander is a critically-acclaimed author, poet, educator, and scholar. Her book, The Trayvon Generation (Grand Central Publishing, 2022), is a must read. It is short, at only 130 pages, so there is no excuse for even the slowest reader like me to not get through it in a timely manner. It is not a rehashing of the Black history that whites already think they know. It is deeply personal, and highly illuminating.

Alexander draws on the works of other Black scholars, writers, and artists to literally and figuratively illustrate her points throughout the three-part text. The images of these creators, and the images created by Alexander’s eloquent prose, are moving, haunting, and indelible.

One chapter is entitled “whether the negro sheds tears.” The question, asked of the Black scholar W.E.B. Du Bois in 1905 by a (presumably white) researcher, parallels another query I addressed here previously: “Do Insects Feel Pain?” The implication of the question is similar to what Alexander concludes about questions of Black emotional expression:

”Are Black people human? Do Black people do what people do. Are Black people people. If Black people are not people and do not cry, then they do not experience pain, or grief, or trauma, or shock, or sorrow. If Black people do not experience pain, or grief, or trauma, or shock , or sorrow, are they human? And if they are not human, can their continued violation be justified?”

The artifice of race cannot stand, but Alexander allows for you to come to that conclusion. She demonstrates how even she herself once experienced the “shock of delayed comprehension” at the normality of white supremacy and expectation of Black servitude in the form of a painting of Elihu Yale with this Servant, hung prominently in the Corporation Room at that Ivy League university where she worked. She had failed to previously notice the servant in the painting, or mentally censored the offensive nature of the portrait.

Many such examples abound in our daily lives but we have been conditioned to accept them as normal, as acceptable. Recognition of artworks depicting white supremacy, hostile government and business policies, mass incarceration, wage gaps, and other obscene transgressions against people of color is what is met with anger and outrage by people who stand to lose power.

I care not one whit if I lose “followers” as a result of urging you to pick up The Trayvon Generation and begin a journey toward true humanity that embraces all beings, and takes action to make it so. Imagine the heights to which our species could climb were we to extend white privilege to all ends of the human spectrum.