Meeting Abstract
Semi-arid rangelands of the western US are sensitive to climate change, with droughts projected to increase in frequency and duration in the latter half of the 21st century. These extreme events also impact many insect populations. We hypothesized that if drought could prolong diapause of Mormon cricket eggs, it might synchronize embryonic development and hatching after moisture is restored. We compared a high elevation WY population with two (OR and ID) at lower, drier elevations where we predicted the eggs would be more tolerant of desiccation. We predict that eggs will show the least development in drought during the first growing season, but the undeveloped eggs in the driest treatments will show the greatest development following restoration of moisture and a second growing season. For WY, the two drier treatments had significantly more eggs prolonging development until after the first warm period than the two wetter treatments. Whether those eggs in prolonged diapause developed in the second or subsequent warm periods did not differ among moisture treatments. Significantly fewer OR embryos developed at the driest treatment compared to the others, and almost all of the ID eggs developed irrespective of the moisture treatment. In conclusion, Mormon crickets can delay embryonic development to avoid drought until favorable conditions for growth and hatching are restored. Because undeveloped eggs lose less water than developed embryos, plasticity of WY mitigates the drought effect on egg viability. Eggs from high elevation were the most tolerant due to their capacity to postpone development to any one of several more favorable growing seasons. OR also reduced egg loss by prolonging diapause relative to ID that developed in even the driest condition. Although drought did not result in a concentration of development, diapause plasticity allowed the katydids to await more favorable conditions.
