Meeting Abstract
P1.66 Tuesday, Jan. 4 Does embryonic diapause help maintain of milk quality? A case study in bats. ORR, T.J.*; ORTEGA-REYES, J.; MEDELLIN, R.; HAMMOND, K.A.; UC, Riverside; Instituto Politécnico Nacional; UNAM; UC, Riverside teri.orr@email.ucr.edu
Predictable and reoccurring environmental stressors can result in pressures for organisms to develop highly-timed reproduction. One interesting response to environmental variation in resources are reproductive delays or temporal pauses in reproduction. These pauses may occur between copulation and fertilization, fertilization and implantation, or after an embryo has implanted. It is generally believed delays allow animals to time expensive stages with food availability. However, because the assumption that delays are adaptive has not been well tested, we investigated the costs and benefits of delays in a unique species of bat that possess both delayed and non-delayed pregnancies. Artibeus jamaicensis, the Jamaican fruit bat, has two annual pregnancies, one with delayed in-utero development and one with no delay. We compared female fat stores and milk composition between the two pregnancies for free living bats relative to food availability to test of the hypothesis that delays allow females to synchronize the most expensive stage of reproduction, lactation, with food abundances. We also present new data from a closely related species that was believed to have reproductive delays, Artibeus hirsutus, the hairy fruit bat. Our research reveals that 88% of A. hirsutus give birth late February, pup sex ratio is roughly 1:1 9 (M:F), and that the uterus of is simplex like other members of the genus. Our data on milk composition is the first description of milk in this species. To conclude we compare and contrast the reproductive ecology and biology of A. hirsutus to other members of the genus specifically A. jamaicensis in the context of delays. This information may elucidate important features for conservation of mammals that exhibit reproductive delays and contribute knowledge to those interested in the evolution of reproductive delays.
