Nuptial gifts increase egg number and hatch rate in a Hawaiian cricket
Contributed by: Biz Turnell @BRTurnell
Keywords
Animals, Evolution, Evolutionary processes, Field, Forest, Fundamental research, Lab, LGBTQIA+, Natural selection, Non-binary, North America, Observational, Sexual selection, Transgender
Slides
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View and download in google slides here
Resources
Biz R. Turnell and Kerry L. Shaw. 2015. High opportunity for postcopulatory sexual selection under field conditions. Evolution 69(8):2094-2104 link
Bon Appétit! Why do male crickets feed females during courtship? http://datanuggets.org/male-crickets-feed-females-during-courtship
Popular science article link
Notes
Slide 1: Researcher’s Background
Biz is an evolutionary biologist, most recently at the Technische Universität Dresden, in Germany. Their doctoral and postdoctoral research focused on postcopulatory sexual selection, especially the patterns and mechanisms of sperm allocation, storage, and use. They now work as a science editor.
PB: Why did you become a biologist?
BT: I have always loved nature and am especially fascinated by animal behavior. When I found out you could watch animals behave for a living, I was sold!
PB: What is your favorite part about your job?
BT: I enjoy learning new things every day and getting to the bottom of tricky questions. That still fits my job description now that I work as a scientific editor instead of doing research myself.
PB: What obstacles have you overcome to get where you are?
BT: I am extremely lucky to have come from a very supportive and privileged background. My luck continued in graduate school, where the students, staff, and faculty in my department were likewise supportive during my transition. Still, it was a tough process and it took a lot of mental and emotional energy away from my research for a while.
PB: What advice do you have for aspiring biologists?
BT: There are so many directions to follow in biology that it can be a challenge to figure out your options. Talk to as many people as possible and get some hands-on experience to develop your interests. If you can, volunteer, intern, or do a research project for credit at a local museum or college/university. Finding a good mentor is also really helpful, so don’t be afraid to reach out to teachers and professors. Finally, failure is part of the process. If something doesn’t work out the first time, keep trying!
PB: Do you feel that any dimension of your identity is invisible or under-represented/marginalized in STEM?
BT: Yes
PB: Can you elaborate on your answer above?
BT:
Despite growing awareness and acceptance, transgender individuals still face serious challenges and discrimination that can make it difficult for them to achieve their educational and professional goals. A report by the National Center for Transgender Equality found that over three-quarters of openly transgender individuals experience harassment in school and at work, with many students dropping out because of it and many employees being fired or denied a promotion based solely on gender identity [1]. Unfortunately, STEM fields can be especially unwelcoming to trans and gay individuals. A survey of federal employees found that 20% fewer LGBT individuals were employed in STEM-related agencies than would be expected based on their representation in other agencies; and that these workers reported more negative workplace experiences than both their non-LGBT STEM colleagues and their LGBT counterparts in non-STEM agencies [2]. Transgender biologists are also severely underrepresented in academia, based on estimates by Joan Roughgarden, a prominent transgender professor emerita of evolutionary biology at Stanford University and author of “Evolution’s Rainbow: Diversity, Gender, and Sexuality in Nature and People”.
[1] Grant, J. M., L. A. Mottet, and J. Tanis. “Injustice at every turn: A report of the national transgender discrimination survey.” Washington: National Center for Transgender Equality and National Gay and Lesbian Task Force. 2011.
[2] Cech, Erin A. “LGBT professionals’ workplace experiences in STEM-related federal agencies.” 2015 ASEE Annual Conference & Exposition. 2015.
Slide 2: Research Overview
Take home message of study
In Hawaiian Laupala crickets, the male produces a series of spermless “microspermatophores” during courtship and transfers them to the female, who eats them. The more of these nuptial gifts (“nuptial” means “wedding”) the female gets, the more eggs she lays and the more of those eggs hatch.
Study system
Male L. cerasina (left) with a sperm-filled macrospermatophore ready to transfer to the female (right), after all of the microspermatophores have been transferred. Male and female are marked with paint for individual identification.
Slide 3: Key Research Points
Main figure
(A) The total number of eggs a female lays in her lifetime increases with the total number of spermless microspermatophores (nuptial gifts) she receives from all of her mating partners put together. This effect was significant in a lab-based experiment where females mated with three different males (orange points and regression line), but not in a field-based experiment where females were allowed to mate with an unlimited number of males (blue points and regression line).
(B) The hatch rate of a female’s eggs increases with the total number of microspermatophores she receives. This effect was significant in both experiments.
Societal Relevance
In many insects, spiders, and other animals, males transfer “nuptial gifts” to the female during courtship. These gifts include prey items, parts of the male’s own body, glandular secretions, and sperm-containing packages called spermatophores. These gifts can play a major role in sexual selection, both precopulatory (e.g., mate choice) and postcopulatory (e.g., fertilization success). However, their specific functions are often unknown.
