P3.167 Friday, Jan. 6 Did social monogamy evolve as part of a sedentary lifestyle in Lysiosquilloid mantis shrimps? WRIGHT, ML*; STEVES, I; CALDWELL, RL; UC Berkeley; UC Berkeley; UC Berkeley firstname.lastname@example.org
Although social monogamy, when a male and female live together for at least one breeding season, is characteristic of several ecologically important crustaceans, little is known about the evolution of social monogamy in crustaceans. In Lysiosquilloid mantis shrimps, social monogamy occurs in eight genera. Many mantis shrimps are sit-and-wait predators that seldom leave their burrows. This sit-and-wait feeding strategy may confer fitness benefits by decreasing vulnerability to predators and increasing energy available for reproduction. However, since foraging and mate searching often occur simultaneously, sit-and-wait predation may decrease mating opportunities, leading to the evolution of social monogamy. To investigate whether the evolution of social monogamy is associated with the evolution of sit-and-wait predation and burrow dwelling in the Lysiosquilloidea, we conducted a phylogenetic comparative study using behavioral, ecological, and morphological data. We hypothesized that social monogamy would evolve more often in burrow dwellers living in soft-bottom substrates We also hypothesized that the body shape (thorax and abdomen) would lengthen for better maneuvering inside the burrows. We used geometric morphometrics to characterize the body shapes of 44 mantis shrimp species. We digitized dorsal body shape by placing 21 landmarks on the abdomen and thorax and obtained shape data of landmarks using Procrustes superimposition. A mantis shrimp maximum parsimonly tree of 103 taxa was constructed using a concatenated matrix of genetic (12S, 16S, 18S, CO1) and morphological data (Ahyong 2001). Data on the social mating system, habitat, depth range, and foraging strategy of each species were collected from the literature. Using ancestral reconstruction and PGLS, we analyzed the associations between relative warps of the shape data, social monogamy, predation strategy, and habitat preference.