True bugs, also known by their scientific name- Hemipterans, are an order of insects that use piercing and sucking mouthparts to consume prey. Belostomatidae is one family within hempitera currently containing eight described genera. The genus Belostoma is smaller in size, and tends to feed on smaller invertebrate prey, while a second more distantly related genus, Lethocerus, is much larger in body size and known to feed on small fish, reptiles, and amphibians. We wished to know if this diversification in prey selection also represents a diversification in the venom used to hunt different animal types. To test this we extracted and analyzed the venom from multiple Belostomatid species representing an evolutionary diversity of the family: Lethocerus americanus, Lethocerus medius, Abedus herberti, and Belostoma fluminium. We then compared the relative protein size composition and functional performance of each species’ venom to determine if venoms are similar or different among genuses. We predicted that if venom composition and functionality is similar among species, larger volumes of venom will be associated with larger species.Venom was collected over 10 weeks from 2 L. americanus, 1 L. medius, 5 A. herberti, and 22 B. fluminium. We also extracted from 4 B. flumineum that were collected and raised in a different region of N. America, which were kept separate from the locally occurring B. fluminium to test for regional differences that may be indicative of speciation events. B. fluminium produced a mean mass of 0.65mg of venom per individual insect, whereas the remote B. fluminium had a mean mass of 1.08mg per individual. While the mean venom collected from the remote B. fluminium individuals was greater than local specimens, the total mass for all B. fluminium was generally smaller than that of the larger species. The mean mass of venom extracted per individual from the remaining species were as follows: A. herberti, 1.44mg, L. medius, 1.30 mg, and L. americanus, 1.47mg. From this data, we conclude that larger sized Belostomatids produce larger volumes of venom. To compare the general protein composition and functional performance of the toxins, extracted venoms were pooled, frozen, and lyophilized to stabilize protein components. An SDS PAGE gel was then run with samples to test for different size protein compositions among species. Additionally, a functional dilution analysis was performed using monocultures of chicken embryonic cells followed by a cell viability assay to compare the relative toxicity of each species’ venom. Funding for this project was provided by Union College Undergraduate Research Grants. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Read full abstract