Thursday, July 12, 2018

An Insect "State of the Summer" Report

Here in Colorado Springs, Colorado, and elsewhere in the state, it has been anything but a normal summer. Not that there is any such thing as "usual" in this age of aridification and climate change, of course. What follows are personal, anecdotal observations related to weather, insect diversity, and insect abundance so far this season.

Mammatus clouds signal impending hail
Weather

There are only three words needed to describe the weather this summer: Hot, dry, and stormy. We have had recent stretches of ninety-plus degree days, well above the expected average. The excessive heat has been punctuated by severe thunderstorms. At our home, we have had more hail events this year than in the five-plus previous years that I have lived here....and we were lucky. One major hail storm dumped baseball-sized ice balls on the city of Fountain, just a few miles down the highway from Colorado Springs. Repairs to vehicles and roofs and other damaged property will take months and cost many thousands of dollars.

Accumulated hail in our backyard today!

Beyond the city, at least fifteen wildfires have burned thousands of acres of forest and grassland, rendering wildlife habitat and recreational destinations unfit for man or beast for years to come. That does not even address the human dwellings and other structures that were lost in the blazes. Now, heavy rains like we had at our home today will cause flash flooding over the burn scars, and lead to water damage at the bottom of slopes.

Aristotelia elegantella, a tiny twirler moth new to our yard
Insect Diversity

Insect diversity appears....relatively stable, though it is difficult to assess for reasons that will become clear later in this story. Interestingly, every time I turn on our backyard blacklight I seem to attract some species new to me and new to our growing "home list" of animal organisms that now exceeds 440 taxa (levels of classification from Kingdom to species and every level in between). I have managed to excite even seasoned moth experts with some of the nocturnal Lepidoptera that are turning up. We have even had a pine sawyer (Monochamus clamator) and bark beetles (Dendroctonus sp.) come to the blacklight. I suspect someone brought firewood down out of the mountains and the beetles are emerging from it.

Spotted Pine Sawyer, Monochamus clamator
Insect Abundance

Numbers of individual insects are way down. I have to work hard just to find species normally overwhelmingly present. It is this situation that has made assessing diversity more difficult. It is disturbing to note how few insects there are visiting wildflowers, but wildflowers are fewer and farther in between, too, smaller in size and lower-growing than usual, making it difficult to detect them, let alone any pollinators. Yellow Sweet Clover, Melilotus officinalis, an exotic invasive that is now well-established throughout the U.S., and its relative White Sweet Clover, are overwhelmingly abundant this year. They normally attract plenty of pollinators, but I find almost none.

Overwhelming parasitic mite load on Melanoplus sp. grasshopper

Another worrisome observation is that the few arthropods doing well are mostly parasites of other arthropods. Parasitic mite loads on grasshoppers are in some instances frighteningly high. Bee flies are doing well but their hosts, solitary wasps and bees among others, are not prospering. Cuckoo wasps and cuckoo bees are at about average density and distribution.

Bee flies, like this Poecilanthrax arethusa, seem to be doing fine

Even the European Paper Wasps nesting on our back gate have failed to produce more than about two new workers the entire summer so far. That is shocking since they are among the most successful of social predatory wasps.

The New Normal?

Should this year be the beginning of a trend, it would be devastating. Our drought-stricken landscape needs to be watered with historically normal rain patterns or another Dust Bowl will be upon us, threatening not only wildlife diversity but human sustenance in the form of crops and livestock. The forest wilderness cannot take further fragmentation if wildlife populations are to endure, especially large predators that require vast individual territories for hunting and rearing offspring. We need to start treating our own properties as potential wildlife habitat, planting with native vegetation. It may be that we also need to assume some degree of latitudinal climate change and plan accordingly, adopting drought-resistant cultivars into our landscaping.

Our backyard milkweed garden ravaged by today's hail

What are you observing where you live? Share your stories and concerns and possible solutions. This blog is a community built by all of you, please speak up.

6 comments:

  1. I remember that last year was such a great year for butterflies here. When I hike I still see them once it warms up - here in town, not so much - only a few. Not noticing as many grasshoppers as last year, but last year was cooler and wetter too. Not hearing as many cicadas I think either. Saw tons of moths on my hike yesterday.

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  2. SE Wisconsin: Lot's of Japanese Beetles :( We currently have 5 nice-sized Monarch larvae on A. incarnata (Swamp Milkweed) and see Monarch butterflies daily (at least two a day). For a basic 'yard' I'm seeing a fairly good variety of insects, and have good amounts of bees, ants and spiders. We haven't ad many stormy days. So far I've found a fair number of tree cricket nymphs. I saw more as very young ones.....hopefully they are more mature and better at staying hidden -- and the Japanese Beetles are not fond of eating tree crickets.

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  3. I'm seeing fewer species and much lower numbers of insects in my Roseville, Minnesota backyard this year. When I first noticed the decline, I thought it was just an aberrant year or that maybe the neighbor sprayed, but the trend has been downward now for the last five years or so in both numbers of individuals and number of species. I can't think of a single species that is better represented this year over last year; bees are down, Wasps are down, flies are down, beetles are down.... And I'm not finding all that many spiders, especially jumping spiders. Nor ants.... Troubling...

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  4. Oh that seems scary in that part of the world. I've always been also posting some anomalies and abnormalities caused by the weather patterns in our hot tropics. Though we only have two seasons, Dry and Wet, the conditions within are so abnormal these past few years. But being just a new butterfly and moth hobbyist, i still don't know the differences within or among them.

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  5. I'm a long way away from you, up on Vancouver Island. I'm seeing very few insects or spiders this summer. The weather has been more or less normal for this area; changeable, tending to warmish and wet. But the usual populations of insects just aren't showing up. The counts of any species that I've seen are all, except for cellar spiders and some large crane flies, are all in the single digits. I can't remember seeing even one harvestman, nor any bald-faced hornets, usually present in great numbers.

    Bird counts are down, too. I guess that's to be expected, with no insects for the nestlings.

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  6. In Durham, NC, we have fairly normal numbers of buckeyes and silver-spotted skippers, but not many other butterflies of comparable sizes. Two years ago, we had abundant tiger swallowtails and frequent black swallowtails. Last year these were greatly reduced in numbers, and almost nonexistent this summer. We have parsley and fennel plants in several locations in our yard, but they are untouched.

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