Exploring extreme size variation and its implications for mating interactions in the mantidfly, Dicromantispa sayi

Sunday, November 13, 2022

2:54 PM – 3:06 PM PT

Location: Vancouver Convention Centre, Meeting Room 208/209

Presenting Author(s)

LL

Laurel Lietzenmayer (she/her/hers)

Postdoc
University of Florida
Gainesville, Florida

Co-Author(s)

Lauren M. Goldstein

Master's Student
Michigan State University
East Lansing, Michigan
JP

Josephine Pasche

University of Florida
Gainesville, Florida
LT

Lisa Taylor

University of Florida
Gainesville, Florida

In sexually cannibalistic animals, the relative sizes of potential mates often predict the outcome of aggressive encounters. Mantidflies are spider egg predators as larvae and generalist predators as adults, sometimes preying on each other. Unlike most cannibalistic species where one sex (usually females) is consistently larger than the other, individual mantidflies can be substantially larger than other individuals regardless of sex. Using preserved collections of Dicromantispa sayi, we identified three positively correlated body size metrics (head capsule width, pronotum length, subcostal vein length) that were measured consistently and reproducibly across specimens and institutions. We found extreme size variation in both sexes: the largest 10% of females were 1.72x larger than the smallest 10%, and the largest 10% of males were 1.65x larger than the smallest 10%. On average, females were 7.94% larger than males. In exploring possible causes of this variation in adult size, we manipulated larval diet and uncovered differences among populations. We reared mantidfly larvae on egg sacs from two jumping spider species with small or large egg sacs. Mantidfly larvae reared on small egg sacs were smaller than those reared on large egg sacs. This study provides the groundwork to design ecologically relevant experiments exploring the causes and consequences of extreme size variation in an understudied system with intriguing natural history.