Analysis and description of burrow structure in four species of freshwater crayfishes (Decapoda: Astacoidea: Cambaridae) using photogrammetry to recreate casts as 3D models

Abstract

AbstractFreshwater crayfishes use burrows for predator avoidance, desiccation prevention, foraging, and brood care. Based on their burrow ecology, crayfishes can be categorized as tertiary, secondary, or primary burrowers, with primary burrowers being semi-terrestrial and highly dependent on burrows for survival; secondary and tertiary burrowers have decreased burrow dependence and complexity. There has been limited investigation into the specifics of burrow structure. We investigated the factors that influence the structure of crayfish burrows including habitat structure and crayfish through the use of burrow casting and photogrammetry to recreate casts as 3D models. Examined species include the primary burrowing Lacunicambarus aff. diogenesGirard, 1852 and Creaserinus fodiens (Cottle, 1863), and the tertiary burrowing Faxonius rusticus (Girard, 1852) and Faxonius propinquus (Girard, 1852). Crayfish burrows (N = 17) were filled with polyester resin and cured burrow casts were excavated, and photogrammetry was used to recreate casts as 3D models. Burrow depth, number and widths of openings, number and widths of chambers, and number of ancillary tunnels were recorded. Differences in burrow features were analyzed by field site/habitat and crayfish species using stepwise linear regression, MANOVAs, and multiple factor analysis (MFA). From stepwise linear regression, “species” was a better predictor than “habitat of burrow structure.” Burrows constructed by L. aff. diogenes were significantly larger and have more chambers than burrows constructed by the other species examined; burrows of C. fodiens were significantly deeper than those of tertiary burrowers. Each species also created a stereotyped burrow shape. The morphometric differences between burrows of primary and tertiary species illustrate the relevance of these informal classifications. Differences between primary and tertiary species may be related to the species social behavior and ecology.