Insect Ecology @ Au Sable - spring 2023

Pickerel Lake My notes:      Pickerel Lake is a modest lake, with camping spots and some housing around the shoreline. It is relatively small and quiet and is tucked into the southeastern corner of Kalkaska County, Michigan. It is presumably named for its population of walleye (also known as pickerel). The lake is stocked with bluegill, bass, pike, walleye, and yellow perch ( Michigan Sportsman ). Pickerel Lake is known to the locals as a decent fishing spot with large pike, but the fish are notoriously “wily” and easier to catch when it’s iced over ( Michigan Sportsman ). Covering over 100 acres, Pickerel is about 72 feet deep toward the middle parts ( Pickerel Lake Map ). The shorelines are relatively undisturbed, providing an important habitat for many birds, amphibians, insects, and aquatic plants. Our entomology class got to the Pickerel in mid-morning, around 9:00am. The air was cool, about 70 degrees F and rising, and the sky was clear. After we scouted out where

Bog Bear Lake Bog, an interesting ecosystem with plenty of organisms living amongst it, is one of the many places that we visited this term. A bog is a floating mass of plant material, mostly sphagnum moss that is present around a lake. Bogs are home to the pitcher plant which, as designed, is a good trap for insects. These are also some organisms that live around the moss. It is accessible to humans, and we, as a class, visited and collected some insects there. We collected both terrestrial and aquatic insects and saw plenty of other vertebrates and invertebrates along the way.   Bear Lake Bog is located just off the highway in Michigan and down a hill. It surrounds a lake a couple of hundred feet wide and is very unique to walk on. We got into waders, which are water resistant type overalls, and made our adventure out. We took along different nets, such as terrestrial and aquatic, to capture insect specimens for further examination. Getting out onto the bog wasn’t that ha

            Nets over our shoulders, bottles falling out of our pockets, aspirators around our necks, we were ready to venture to the far away wilderness of the Au Sable trail and search for insects around Louie’s Pond. Unbeknownst to us, a few years ago, Louie’s Pond was completely dry! Yet today it was full, the air was humid, yet fairly pleasant at 81 ° F. It was 2 PM on May 23rd, and the mosquitoes were biting our ankles and temples. The first catch of the day was a large dragonfly in a net. Next, we found a beetle on a leaf, which we aspirated. Suddenly another beetle darted across the leaf litter, which we skillfully plucked off its path using tweezers. Of course, the highlight of my day was the four garter snake sightings we had while tromping around the pond and trails. Although it may not seem relevant, snakes can be insect predators, especially when higher trophic level animal populations are dwindling, such as during a stressed year in a drought or during habitat destructio

Mechanisms for maintaining hydration 1.        Increasing body water content is a survival strategy in some mosquitoes. Identical water use and excretion rates by two strains of Anopheles mosquitoes, shows higher survival rate for the Arabian species with a higher normal body hydration level than the Gambian species with a lower average body hydration. Ref.  E.M.Gray and T.J.Bradley “Physiology of dessication resistance in Anopheles gambiae and Anopheles arabeinsis” American Journal of Tropical Medicine and Hygiene 73(3):553-559 2.        Some fruit fly larvae Drosphila melanogaster store more more water by producing high levels of glycogen, a polysaccharide of glucose, that fixes five times it weight in water molecules. Ref.  J.L.Graves etal (1992) “Dessication, flight, glycogen and postponed senescence in Drosophila melanogaster” Physiological Zoology 65:268-286 3.        Larger hemolymph volume in some varieties of Drosophila melanogaster is accomplished by produc

By Geof Gaiser Freeze avoidance is clearly the basal characteristic of insects, in contrast to freeze tolerance, an evolved set of traits.  Avoidance is characteristic of cold continental habitats of the Northern Hemisphere, allowing insects to survive very low temperatures for long periods of time, and also to avoid desiccation.  These responses tend to be strongly seasonal, and insects in these habitats are only capable of maintaining their avoidance strategies for the overwintering period in their microenvironment. Strategies of freeze avoidance are seen in the larvae of the goldenrod gall moth, Epiblema scudderiana ,eggs of the Autumnal moth, Epirrita autumna ,  many other insects, and the arachnids – spiders, mites and ticks. Some super cooling points can be as low as -35 to -40ᵒC.  Ref.   B.J.Sinclair et al “Climatic variability and the evolution of insect freeze tolerance”, Biological Reviews, 78:181-195 (2003) The larvae of the goldenrod gall moth mentioned above,