Effects of temperature on larval survival and development in the xanthid crab <i>Atergatis floridus</i> under laboratory conditions

The xanthid crab Atergatis floridus contains paralytic shellfish toxins at levels lethal to humans. Predicting its potential distribution requires understanding the environmental factors that govern survival and development throughout its life cycle. Among these, temperature is particularly critical, as it strongly influences larval survival and development, and thus population connectivity and geographic distribution in decapod crustaceans. We investigated the effects of temperature on larval survival and development in A. floridus. Larvae from two broods were individually reared on rotifers and Artemia at five temperatures (16, 20, 24, 28, and 32°C). At 16°C, all larvae from both broods died without molting, consistent with the lower developmental threshold (15.5–16.7°C) estimated from heat-summation theory equations relating temperature to zoeal duration. Larvae survived to the megalopal stage at 20–28°C in brood 1 and 20–32°C in brood 2, with the highest survival at 24°C and 28°C. The first crab stage was attained at 24°C and 28°C. These results clarify the thermal limits of larval survival and development in A. floridus and improve predictions of the temporal and spatial ranges suitable for its successful recruitment.