Frost Curators' Blog

Musings and miscellanea from the Frost Entomological Museum

Providential parasitoids and netted nepids

Upon returning to the Frost from lunch yesterday, I noticed a little hymenopteran hitchhiker clinging to my shirt – a female trigonalid wasp!

Lycogaster pullata. Photo by Salvatore Anzaldo (CC by 2.0).

Apparently these are pretty rare wasps, and the reason for that is their remarkable life cycle:

  • Large amounts of minuscule eggs are laid at the edges of leaves, accomplished with a pretty strange abdomen.

    The leaf gets clamped between the awl (spine at the middle of image) and the armature (to the left of awl). Possibly an egg above the armature? Photo by Salvatore Anzaldo (CC by 2.0).

 

  • The eggs hatch when they are eaten by a caterpillar (in this case, a saturniid or arctiid)
  • Once inside the caterpillar, the wasp larva survives only if the caterpillar is already being parasitized by another wasp, like an ichneumonid. The trigonalid larva proceeds to parasitize the other parasite (hyperparasitism!)
  • If the caterpillar isn’t already parasitized, but gets chewed up by a vespid or potter wasp to be fed to it’s own larvae, the trigonalid larvae will parasitize that larvae.

There was only one trigonalid specimen in the Frost (at least where they should be in the collection), and it’s a male Orthogonalys pulchella collected in State College in 1982… now we have two!

 

Now to change gears to our collecting trip back to Ten-Acre Pond on Monday: I spent much of it with a D-frame net in hand searching for some aquatics, specifically a water scorpion (one of my favorites). And, somewhat unexpectedly, after a long time dip-netting, I got one!

Not dip-netting at the moment, but standing right next to where I found the nepid. Photo by Andy Deans (CC by 2.0).
“I’m not a nepid… I’m a stick!”. Photo by Salvatore Anzaldo (CC by 2.0).
Ranatra sp. Photo by Salvatore Anzaldo (CC by 2.0).

The lousiest week

The word “lousy” is used to describe something bad because it originally meant “infested with lice”, which I suppose would be an unpleasant thing. By the “lousiest” in the title, I also mean “filled with lice”. However, “My fantastic past week” would be an acceptably interchangeable title. With my project in need of the capture of a live gasteruptiid wasp, and me failing to catch one (no longer an issue – thanks Brian!), I undertook the task of profiling and cataloging the K.C. Kim Louse Collection at the Frost, knowing next to nothing about lice except for an outdated conception of louse taxonomy and even less about their hosts.

So here’s a condensed version of all the Phthirapterally phthrilling phthings I’ve learned in the past week, about lice in general and K.C. Kim’s collection. I’ll start off with some impressive figures about the collection.

  • All four suborders are represented in more than 15,000 slides and around 390 species
  • There are lice from every continent. Even Antarctica!
Antarctophthirus lobodontis taken off of a crabeater seal in Cape Crozier, Antarctica. Photo by Salvatore Anzaldo. CC by 2.0.
  • The oldest specimen is around 400 years old!
Pediculus humanus capitis off of the head of an Aleutian Eskimo mummy from the 17th Century. Looks pretty good for 400. Photo by Salvatore Anzaldo. CC by 2.0.
  • Over half of the approximately 500 known species of Anoplura, or sucking lice, are present.

Sure, lice have some pretty disgusting habits by human standards. But what I’ve come to appreciate is how successful they are at the ectoparasitic lifestyle and how well adapted they’ve become to their hosts (and sometimes specific parts of their host). Look at the differences in the tarsal claws in these images – if they cling to hair or feathers, they grasp it between the tarsal claw and an extension of the tibia. If they don’t cling to hair or feathers, their legs look like a typical insect leg (like the image below).

Piagetiella peralis, which can be found inside the mouth pouch of the white pelican. Photo by Salvatore Anzaldo. CC by 2.0.
Close-up of the wicked mandibles of Piagetiella peralis (a “chewing louse”) used to break the soft skin of pelican mouths. Photo by Salvatore Anzaldo. CC by 2.0.
Haematomyzus elephantis, off of an Asian elephant. The elongated “snout” is used to bore into the thick skin of elephants. Photo by Salvatore Anzaldo. CC by 2.0.
The family Boopidae contains chewing lice that specialize on marsupials. This one was removed from a bandicoot. Photo by Salvatore Anzaldo. CC by 2.0.
Hybophthirus notophallus from an aardvark. Collected in the Bechuanaland Protectorate (now Botswana) in 1965. Photo by Salvatore Anzaldo. CC by 2.0.
Lepidophthirus macrorhini from an elephant seal. When elephant seals take their long treks to sea, these guys venture under their skin to withstand the pressure of a deep dive. Photo by Salvatore Anzaldo. CC by 2.0.

 

If you’re still not crazy about lice… they’re sometimes mounted on slides in a way that looks like they want hugs!

This Pecaroecus javalii wants a hug!     Of peccary flesh. The structure visible inside the head diverging to the left of the midline is the modified labium of “sucking lice”. Photo by Salvatore Anzaldo. CC by 2.0.
Phthirunculus sumatranus, off of the red giant flying squirrel of Sumatra. Photo by Salvatore Anzaldo. CC by 2.0.

 

After all that I’ve definitely been inspired to go on a mission to collect my first louse!

 

The enigmatic extremities of carrot wasps

Here’s a little about my summer research project and what I’ve done so far:

I’m looking inside part of the leg of a type of parasitic wasp in the family Gasteruptiidae.

  • Common name: Carrot wasps, because they are often seen on flowers in the carrot family, Apiaceae. 
  • Behavior: Cleptoparasites of solitary bees. Not a whole lot is known about larval behavior or the host associations of most species. Sometimes the growing larvae eat just the food provided for the bee larva, and sometimes they eat the food and the larva.
Gasteruption floridanum male. Photo by Salvatore Anzaldo (CC By 2.0)

You may notice on the above image the seemingly swollen part of their hind legs (the tibia), and that’s what I’m exploring.

Close up of hind tibia. Photo by Salvatore Anzaldo (CC By 2.0).

Other parasitic wasps have tibiae that are similarly enlarged, but only in female wasps – within the leg is an enlarged organ (the subgenual organ) that allows them to detect vibrations of potential hosts (in wood, soil, etc.) so they can lay their eggs in them.

The hind tibiae of gasteruptiids are unusual for two reasons:

  • It is enlarged in both males and females.
  • Inside, it looks like this:
CLSM image of a longitudinal section of hind tibia. Photo by Istvan Miko (CC By 2.0).

I’m trying to figure out:

  1. Is the subgenual organ enlarged?
  2. Are there differences between the male and female legs?
  3. What are the spherical structures that are fluorescing yellow-green in the above image?

To try to answer these questions, I’ve employed the technique of histological sectioning, which uses a machine called an ultramicrotome (in essence a tiny deli slicer that can make slices a few nanometers thick, or in this case, 1.5 microns thick). After sectioning, the slices get stained:

Cross section of Gasteruption assectator hind tibia. Photo by Salvatore Anzaldo (CC By 2.0).

What’s visible in this picture?

  • The outer pinkish-red ring is the cuticle.
  • The purplish-blue rectangular structures on the inside of the cuticle are the epidermal cells. Epidermal cells secrete the cuticle, and together they make up the integument that protects the insect from its environment.
  • The circular purple structures are the mystery spheres. Of the nine shown here, four were sectioned at a level that shows the center (in pink), apparently of a different composition as the rest of the structure. The most I counted in one section was 22.
  • The spongy-looking material in the center – I have no idea what this is, but my guess is that it has something to do with the spherical structures.
  • The large empty space at the left (mostly cut off in this picture) is a trachea.

To get a closer look at the spherical structures, I imaged them again with the CLSM:

Spherical structures at 100x. Photo by Salvatore Anzaldo (CC By 2.0).

In the two spherical structures shown above, the inner part is fluorescing bright green, and the outer portion is fluorescing darker green and is peppered with orange spots.

So, to answer my above questions as best I can right now:

  1. Is the subgenual organ enlarged? I don’t think so.
  2. Are there differences between the male and female legs? I don’t think so.
  3. What are the spherical structures? I have no idea.

Next step – catch another wasp, section it, and image it with TEM for an even closer look.

Profiling a slide-mounted insect collection

We’ve been systematically evaluating (“profiling” in curators’ parlance) the condition of the Frost Museum research collection for the last few months, an exercise that should give us a better idea of which areas of our holdings need special attention. The pinned collection and Odonata have been scored already, and the results are about what you’d expect for an older collection (no overly nasty surprises, thankfully). More on that later. Up next is an exploration of our slide-mounted insect collection. I don’t have a lot of experience with slides, at least historically, so here’s a brief solicitation of feedback.

Our scoring system for the pinned material went from 0–7, with 0 reserved for the worst of the worst (an emergency curation situation, involving loose specimens, dermestid pests, etc.), and 7 referring to a container (drawer) that is fully digitized and perfectly curated. What would a 0–7 scale look like for a slide collection? Our scorable unit is a slide box. Here’s a draft:

0 = slide box has lost its structural integrity (won’t close, bottom falling out, etc.) or the slides inside are unlabeled or broken or slide labels have fallen off. Here are three examples of what I would score as a 0:

The original slide box must’ve been compromised, and the solution was to move all the slides into a cigar box. Cripes. Photo by Andy Deans (CC BY 2.0)
This slide box has lost its integrity and is now a hazard to its contents. I almost didn’t notice it when I removed the box from the shelf! Double cripes. Photo by Andy Deans (CC BY 2.0)
Slide slats are too far apart in this box, which led to half the slides flopping around in the box, unsecured. Photo by Andy Deans (CC BY 2.0)

Ok, A profile score of 0 seems easy to define. What about the other levels?

1 = Container is sound, if not ideal (that is, it doesn’t match the rest of your system), but it holds a broad mix of taxa, from mites (Acari) to fleas (Siphonaptera) to whatever; it’s not a loanable unit.

2 = Container is a standard 100-slide box, in good shape, and is labeled on the outside. Specimens are determined minimally to family and sorted accordingly (i.e., a box contains one family); these are loanable units. Specimens aren’t necessarily mounted in an archival medium (e.g., some might be in Hoyer’s).

Slide has a unique identifier and appears to be very well done (clear prep, Canada balsam medium, specimens’ sexes are determined). Specimens are not determined below “Anoplura”, though, and the container was labeled only with the host’s species name, Tatera indica. How would this lot score? Is a 2 too harsh? Image by Andy Deans (CC BY 2.0)

3 = Slides are stored horizontally in a box that meets the conditions outlined for a score of 2. Specimens are preserved in Canada balsam and are clearly visible (they’re good preparations). Material might not be incorporated into main collection (e.g., a returned loan, sitting in a receiving section of the shelf). Specimens determined minimally to species.

4 = Material is part of main collection, but the box may not have standard header cards, and/or no expansion space. Slides have unique identifiers. Taxon names have been cataloged.

5 = Header cards are there for each taxon, along with adequate space (minimally 20%) for additional new material within box. Number of specimens per taxon is documented in the catalog.

6 = Specimens arranged by collecting event, and data captured digitally, perhaps using non-standard method (spreadsheet, word processing file, alternative database).

7 = All specimens databased for collecting event, georeference, species name and author. Data are readily available through the World Wide Web.

Anything missing? We have an incredible array of slides, built up over the decades by John O. Pepper (aphids expert, now deceased) and former curator K. C. Kim (Anoplura expert, still active) so I expect this collection to profile well!

A passalid by any other name…

Bessbug, bess beetle, betsy bug, horn beetle, horned passalus beetle, peg beetle, patent leather beetle, and Jerusalem beetle – believe it or not, these are all names for a single species: Odontotaenius disjunctus (family: Passalidae).

Odonotaenius disjunctus, a beetle of many names. Photo by Brian Reily. CC BY 2.0

O. disjunctus is a relatively common beastie throughout the eastern US and Canada and can be found in well-rotten oak logs, tending to their young in their tunnel like galleries and feasting on decaying wood-chips and each other’€™s feces. Passalids are one of the few beetles that display any form of social behavior – but for a real shocker check out Austroplatypus incompertus! – in that they tend to their young, feeding them poop and wood until they mature.

The myriad of common names assigned to this species come mostly from traits that describe the beetle or its habits:

      • Bessbug, bess beetle, and betsy beetle are all derived from the French baiser, meaning “to kiss”, and likely relate to the squeaky stridulations they use as a rudimentary form of communication.
      • Horn beetle and horned passalus beetle refers to the hook-like horn on the frons (face) of the beetle.
      • Peg beetle probably describes the appearance of the beetle sticking out of its gallery like a peg.
      • Patent leather beetle comes from the color and texture of this species’ carapace, which is very much similar in appearance to black, japanned leather.
      • The name Jerusalem beetle is an utter mystery to me – I honestly have no inkling where this name came from.

As you may guess, all these common names could create some confusion. I’d like to claim that the solution to this problem is the classical fix which every introductory biology teacher touts to their students as the be-all, end-all of nomenclatural mayhem – namely the latin binomen (or scientific name if you prefer). I’d like to claim this… but in this case I can’t. You see: Odontotaenius disjunctus has had some issues with holding onto its scientific name over the years (a fact evidenced by a recent cataloguing of passalids in the Frost collection).

Here’s a brief (yes, this is brief) rundown of its nomenclatural history:

In 1764, Carl Linnæus described a species of beetle and named it Scarabaeus interruptus, In 1800, the German entomologist Johann Karl Wilhelm Illiger revised Linnæus’s work and assigned the species to its own genus, naming it Popilius disjunctus. The following year, all passalids were moved into the family Lucanidae and placed into the genus Passalus by Johan Christian Fabricius; Popilius disjunctus became Passalus cornutus. The same year, Fabricius’s student, Friedrich Weber, described a new species and named it Passalus distinctus, which was later realized to be distinctly the same species as Passalus cornutus. In 1815, John Henry Leech moved Passalus to its own family, Passalidae.

In 1868, Johann Jakob Kaup took a break from trying to figure out the mathematical order of nature and broke down the genus Passalus, but left Passalus cornutus as such. In 1871, Kaup revised his revision – further breaking down Passalus, resurrecting Popilius, and creating Neleus, but not including Passalus cornutus in the newly revived genus. In 1891, August Ferdinand Kuwert ran into the same issues as Weber, but in greater magnitude, and described a new species of the genus Nelus, Nelus stanleyi; the following year he added Neleus bos and Neleus dollei – all of which turned out to be the same species. In 1896, Kewert erected the genus Odonotaenius and in 1897 he, naturally, placed the species into Neleus in his monograph as Neleus bos.

In 1905, Richard Zang moved the species into Odonotaenius as O. disiunctus [sic], mentioning cornutus as a synonym and causing massive amounts of chaos and confusion. In 1918, F. H. Gravely, despite fixing many of the other problems in Passalidae, returned it to Passalus it as Passalus cornutus; and in 1920 Charles William Leng recorded Passalus cornutus in his Catalogue of the Coleoptera of America North of Mexico. In 1935, W. D. Hincks and J. R. Dibb listed the species as Popilius disjunctus and the 1939 reprint of Leng’s work notes this change.

In 1951, British entomologist W. D. Hincks published a brief note in the Coleopterists Bulletin complaining about the persistent use of the name Passalus cornutus by American entomologists; on the following page is a sharp rebuttal from the editor of the time, R. E. Blackwelder, stating that the American’s had not made this error for at least fifteen years. And finally, in 1970, Pedro Reyes-Castillo reinstated the genus Odonotaenius and gave our species its current name, Odonotaenius disjunctus.

What a mess!

I came across many of the variations as I was cataloguing the collection and organized them into a single location. Until someone publishes another paper and places this species somewhere else, we’re going to refer to this location as “the place where we put Odonotaenius disjunctus.”

The place where we put Odonotaenius disjunctus. Photo by Brian Reily. CC BY 2.0

And now for something completely different!

Check out the chops on this pamphiliid sawfly I found yesterday:

Pamphiliidae. Photo by Brian Reily. CC BY 2.0

I’ve never run into something with non-symmetrical mandibles before!

Department of Entomology, in the College of Agricultural Sciences, at Penn State

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