Monday, January 9, 2017

A Carrion Beetle That Isn't?

At first glance, the Garden Carrion Beetle, Heterosilpha ramosa, could be mistaken for a darkling beetle or ground beetle. Indeed, only the clubbed antennae, and the five tarsal segments comprising each "foot," betray them as something else (darkling beetles have only four segments in the tarsus of the hind leg). Carrion beetles make up the family Silphidae, but surprisingly, this particular species seems to have a diet of anything but corpses.

I periodically encounter the 11-17 millimeter long, dull black adult beetles crossing the sidewalk in my Colorado Springs neighborhood. The natural habitat here is shortgrass prairie, but I knew this beetle when I lived in the coniferous forests of Portland and Corvallis, Oregon, too. It occurs mostly west of the Rockies and south to Mexico, but ranges east and north as far as Iowa, Minnesota, and Ontario, Canada.

Consulting various references paints and interesting and evolving picture of H. ramosa. Older references used the genus name Silpha, but it is the portrayal of the species as at least an occasional pest that is puzzling. Essig declares that the Garden Carrion Beetle feeds mostly on decaying vegetable matter, but "also attacks garden and field crops, grasses, and weeds. If often occurs on lawns." Presumably it consumes these foods as both an adult and a larva.

The larva is jet black, highly mobile, and resembles an overgrown carpet or hide beetle larva (family Dermestidae, especially genus Dermestes). The tapered body allows the larva to slither effortlessly into cracks and crevices, or easily slip out of a predator's grasp. The speed at which it can travel is rather surprising considering the relatively short legs at the front of the body.

A more contemporary book by Jerry Powell and Charles Hogue asserts that the "Garden Silphid" adults and larvae "are general feeders, consuming living or dead, soft-bodied insects such as maggots, which feed on decaying organic matter in the soil; Silpha sometimes feed on leaves of plants at night."

Arthur V. Evans and James Hogue illuminate the natural history of this species a bit more in the most recent reference I could find in my library. According to their Field Guide to Beetles of California, "The adult is active March through October....overwinters and becomes active the following spring. Eggs ar laid in the soil around a carcass or rotting vegetable matter and take approximately five days to hatch.....The larval stage lasts approximately two to three weeks. The pupal stage lasts 8-9 days." The authors go on to recite the previous conclusion that both the adult beetles and the larvae are "general feeders."

The evolution of our understanding of the impact of H. ramosa comes full circle, from minor crop pest to beneficial organism in the rest of Hogue and Evans' life history sketch: "The adult has been found feeding on dead Devastating Grasshoppers (Melanoplus devastator) and Brown Garden Snails (Helix asper)." Ok, so it is scavenging, but considering the predatory nature of other carrion beetles, it would be no surprise to find it killing injured or otherwise incapacitated pest invertebrates, too.

What else do we not know about this species, or any other insect for that matter? The answer is "plenty." Insects which are not perceived to be of economic importance, either positively or negatively, tend to be under-researched, to put it mildly. Outright ignored is perhaps an even better way to frame it. Pick a "bug," any bug, to study, and chances are you can be something of a hero.

Sources: Essig, E.O. 1958. Insects and Mites of Western North America. New York: The Macmillan Company. 1050 pp.
Evans, Arthur V. and James N. Hogue. 2006. Field Guide to Beetles of California. Berkeley: University of California Press. 355 pp.
Powell, Jerry A. and Charles L. Hogue. 1979. California Insects. Berkeley: University of California Press. 388 pp.
White, Richard E. 1983. A Field Guide to the Beetles of North America. Boston: Houghton Mifflin Company. 368 pp.

Friday, December 30, 2016

Looking Forward to the Year Ahead

Male Flame Skimmer dragonfly looking forward through rose-colored eyes?

The new year ahead promises to be challenging in many ways, but hopefully rewarding, too, as I continue in my attempt to bring you topics of relevance to your lives and captivating to your minds, through this blog. I am embarking on a couple of new ventures, and will continue to take my writing in directions away from entomology. I hope you will follow. Resolutions? I have plenty, and I will start with being more grateful for my patrons.

So, first of all I want to again thank those of you who are "following" this blog, those who have donated to it via the PayPal button in the sidebar, those who have paid for advertising here (with my blessing), those who have "shared," re-tweeted, and otherwise expanded my audience, and those who have actively participated by leaving comments, asking questions, and sharing stories of your own. A community like this is a rare thing, and would not exist without all of you.

This blog also caught the attention of a company overseas, and they have invited me to join them in their quest to provide a unique "pest alert" service that will eventually be able to give advanced warning to gardeners of the likelihood that a certain pest will soon be emerging in their geographic area. The Big Bug Hunt is one project of Growing Interactive, a company that produces a variety of apps and other software to aid gardeners all over the northern hemisphere. I will be doing a more thorough write-up about this venture in the coming months.

My current clients appear to be happy with what I am doing for them, so I expect I will be doing "the usual" for the After Bite Insectlopedia, and SpiderID.com, as well as various magazines and other publications. I also have two speaking engagements already on the calendar for January. Really hoping that I will be invited to nature festivals so that I can actually get people out in the field looking at "bugs."

Locally, as president of the Mile High Bug Club, I will be helping to organize events and outings aimed at furthering the club's mission of education about, and conservation of, Colorado arthropods. The club's founder, Bell Mead, originally formed the group in 2008 as a network of people in the arthropod pet "hobby," facilitating care and ethical trade in tarantulas, scorpions, tropical insects, and other exotics. As members moved, lost interest, and otherwise no longer participated, the focus shifted to its current mandate. Thanks to Bell's persistence and diligence, we achieved non-profit status a few months ago.

Among MHBC activities in the coming year will be field trips in search of tiger beetles, dragonflies, grasshoppers, and maybe fireflies and lampshade weavers (a kind of spider). Also on the horizon are the annual National Moth Week events we create and document, plus a series of bioblitz events in celebration of the twentieth anniversary of the Trails, Open Spaces, and Parks (TOPS) in Colorado Springs. We also intend to have a booth in the exhibit hall for the national meetings of the Entomological Society of America, to be held in Denver from November 5-8, 2017. The Big Bug Hunt may share table space with us.

Beyond expressing gratitude more regularly, my personal resolutions include reading more (so look for reviews here and over at Sense of Misplaced), generating more book-length work of my own, and integrating myself into a larger network of other writers. My current network is almost all entomologists and naturalists. My philosophy and goals revolve around empowering others to think differently, act to help make the world a better place, and have fun doing it. I have no interest in amassing personal wealth, accumulating more material goods, or chasing fame and celebrity. I do insist on having my skills, intellect, time, and expenditures valued to the point that I am at least breaking even. More to the point, I will aggressively defend the rights of others to be able to make a living doing what they are best suited to do.

Thank you for continuing on this journey with me. Remember, I am always receptive to topic ideas, recurring themes, and other improvements to this blog. I hope I have been responsive to you thus far. Happy New Year to all of you.

Wednesday, December 14, 2016

Compost Insects

It is the season for sharing, and eating, and if you throw the cooking and table scraps onto the compost heap you are providing a wonderful feast for a variety of insects as well. A recent visit to my in-laws in Illinois, across the Mississippi River from St. Louis, allowed me to discover a multitude of insects over the Thanksgiving holiday, thanks to their compost enclosure.

Having insect activity in your compost is a good thing. It means you have a healthy mini-ecosystem that includes decomposers which break down decaying organic matter into nutrient-rich natural fertilizer. Thus, the vegetable scraps from this year's harvest go on to feed next season's crops. Decomposers are more properly known to scientists as saprophytes, and they often require microorganisms and/or fungi to take full advantage of rotting organic debris.

Look at this yummy buffet!

I did not go digging into the already, uh....fragrant pile of material, but had I done so I certainly would have uncovered a host of invertebrates like springtails, insect larvae, millipedes, maybe woodlice, earthworms, and snails or slugs. Besides food, a compost heap offers insulation from cold weather, and even warmth given off in the process of decomposition.

Minute black scavenger fly, Coboldia fuscipes

Instead of digging and turning, I merely watched for insects appearing on the surface of the pile, or on the walls of the enclosure. These were mostly adult insects, especially flies, the larvae of which are the ones doing the work of decomposition. Chief among these were minute black scavenger flies, Coboldia fuscipes, in the family Scatopsidae. They are only 2-3 millimeters in body length, and can be mistaken for other flies of similar size.

Recently emerged adult minute black scavenger fly

I found a fair number that had just emerged from the pupal stage, with their wings in a rudimentary state awaiting full inflation. Their larvae feed in the mycelia of mushrooms, or on decaying fungal, plant, or animal tissue.

Pomace fly, Drosophila sp.

The next most abundant flies were pomace flies in the family Drosophilidae. Most people call them "fruit flies" because these are the tiny flies that hover around the overripe bananas on your kitchen counter. Indeed, they are drawn to fermenting matter where the females lay their eggs. The larvae feed mostly on the yeasts that invariably attach decaying sugars in fruits and vegetables.

Male Spotted-winged Drosophila, Drosophila suzukii

What was a little surprising was that the common pomace fly species was an exotic one: the Spotted-winged Drosophila, Drosophila suzukii. The males of this species of east Asian origin have an obvious dark spot near the tip of each wing. This fly started appearing in the northeast U.S. in 2011, and has since been recorded over most of the eastern half of the U.S. It is a known pest of a variety of fruits and berries, so it may be one of the few "bad guys" to be seen on your compost pile.

Dark-winged fungus gnat

Dark-winged fungus gnats, family Sciaridae, are abundant pretty much year round, even indoors where the larvae flourish in the soil of overwatered houseplants, feeding on roots and fungi. They are only slightly larger on average than the minute black scavenger flies.

Moth fly

Also present were moth flies in the family Psychodidae. You are probably familiar with their indoor relatives, the "drain flies" that you often see perched like tiny fuzzballs on the bathroom wall or sink basin. The larvae of moth flies enjoy eating algae, bacteria, and fungi, especially if it is exceedingly wet or sludge-like. Yum.

Male Forcipomyia sp. biting midge

Another surprise was to find an adult biting midge, probably in the genus Forcipomyia, or closely-related. Males of these tiny flies have fairly unique, bushy antennae. Depending on the species, the adult females may bite birds or mammals, or suck the blood of moths, dragonflies, and other large insects. Meanwhile, the larvae feed on algae, plant debris, or fungi.

Winter crane fly, Trichocera sp.

The largest fly I found was a winter crane fly, genus Trichocera (family Trichoceridae). It turns out the larvae of these slender, long-legged flies are scavengers on decaying leaves, vegetables, dung, fungi, and material found in rodent burrows. A few are even pests of stored tubers in your root cellar. You do have a root cellar, right?

Predatory mite

The vegetarian "bugs" also attract carnivores in the form of predatory and parasitic insects, and mites. I spotted one mite that made a cameo appearance near another insect I was photographing, but mites are typically among the most numerous of all soil-inhabiting animals. Next in line might be ants.

Japanese Pavement Ant?

I found two species of ants in and around the compost heap. Ants are difficult to identify without putting them under a microscope, but I am pretty sure these were the Japanese Pavement Ant, Tetramorium tsushimae, an Asian introduction now common around the St. Louis area and adjacent Illinois; and the Odorous House Ant, Tapinoma sessile.

Odorous House Ant

The Odorous House Ant is more of a scavenger than a predator, so it is likely to be seeking meat scraps and/or dead insects as sources of protein and fats. It is also fond of sweets.

I saw what I initially mistook for another species of ant, but it became quickly apparent it was a wingless female wasp. The ovipositor (egg-laying organ) protruding from its abdomen betrayed it as a female ichneumon wasp in the genus Gelis. So interesting is this one that you will have to wait for a separate post about it alone. Sorry!

Wingless female ichneumon wasp, Gelis sp.

Another wasp, this one fully winged, was crawling around the perimeter of the top of the wood enclosure. At this time I am unsure if it has any relationship with the compost, or is merely something that blew into the area and became too cold to fly off. I await a proper identification and will supply update this post when I have one.

Unidentified wasp

The benefits of composting to your yard and garden should be obvious, but look at what you are feeding in the meantime: an entire biosphere in miniature, pretty much. Just remember that if you're hungry, they're hungry. Bring them inside. Wait, that's not how it goes....

Friday, December 9, 2016

ID Tip: Seven-spotted or Nine-spotted Lady Beetle?

Today's identification tip involves separating two nearly identical lady beetles: the Seven-spotted Lady Beetle, Coccinella septempuncta, introduced from Europe, and the native Nine-spotted Lady Beetle, Coccinella novemnotata. There is widespread speculation that the exotic Seven-spotted ("C-7") has displaced the native Nine-spotted ("C-9"), and indeed the latter species has become noticeably scarce over most of its former range, especially in the eastern U.S., over the last 35 years or so. That is why it is critical to be able to identify C-9 and report sightings to the Lost Ladybug Project.

Typical specimen of Seven-spotted Lady Beetle ("C-7")

Physical Features

The most dependable, though subtle, difference between these two species is found on the front edge of the pronotum (top of thorax). In the Seven-spotted Lady Beetle, only the corners, or "lapels" if you will, are white. The remainder of the pronotum is black. In the Nine-spotted Lady Beetle, the entire pronotal "collar" is white, so the front edge of the pronotum is white, from corner to corner.

Specimen of the Nine-spotted Lady Beetle ("C-9")

Meanwhile, the wing cover (elytron) of the Nine-spotted Lady beetle does bear an extra black spot, located near the "shoulder." This spot can, however, be vague or even obsolete. The markings on the pronotum are much more consistent.

The Nine-spotted Lady Beetle is usually slightly smaller than the Seven-spotted, and is more often a creamy orange in contrast to the brighter orange, or red, of C-7. Both species are polished (shiny) in texture, and highly convex or nearly hemispherical in shape.

Heavier spots on this C-9
Behavior

There is little difference in behavior between these two species. Both are predators of aphids and can be found on plants hosting aphid colonies.

Another example of the Nine-spotted Lady Beetle
Habitat

Habitat is not a good way to distinguish these two lady beetles, either. Both occur in a variety of ecosystems, from vacant lots, yards, gardens, parks, and forest edges to orchards and agricultural fields.

Complicating Factors

A nearly spotless form of the Multicolored Asian Lady Beetle

There are a surprising number of nearly identical lady beetle species, and simply counting the spots is a very unreliable way of making an identification. There is extreme variability in many species, especially the abundant Multicolored Asian Lady Beetle, Harmonia axyridis, which is yet another non-native ladybug. Not only does the number of spots on the elytra vary, but so do the markings on the pronotum. This species needs to be ruled out before you try and conclude whether your specimen is a C-7 or C-9.

Transverse Lady Beetle

Here in the western U.S., we also have the Transverse Lady Beetle, Coccinella transversoguttata, which resembles C-7 except that the spots on the elytra near the pronotum are connected to form a horizontal black bar between the "shoulders." The Transverse Lady Beetle also appears to be suffering in the wake of C-7's arrival.

Quiz Photo: Which species is this one?

Please keep a lookout for the Nine-spotted Lady Beetle where you live and during your travels. The more eyes in the field, the better will be our understanding of the status of this species, which has been the state insect of New York since 1989. Thank you.