Influence of Temporal Variation on Morphology and Architecture in Burrows of Ocypode Rotundata (Miers, 1882) on Salakh Beach of Qeshm Island, the Persian Gulf

Abstract

Variability over time in morphology and architecture of burrows excavated by Ocypode rotundata was studied on Salakh beach, Qeshm Island, Persian Gulf. According to our results, O. rotundata excavated single Shafts, J-shaped, Y-shaped, spiral and complex burrows, with spiral and complex burrows occurring only in adult crabs. The results showed that mating and reproduction behaviour of O. rotundata mainly occurred in the upper foreshore zone. Based on carapace width data and sex, percentage of J-shaped and Y-shaped burrow were more in female young crabs compared to males. Whilst, percentage of constructed single Shaft, J-shaped burrows were more frequent in male adult crabs compared to females. On the other hand, created complex burrow was observed just in male adult crabs. Also, male crabs created sand pyramid mounds seaward in front of the burrows. Four types of sand disposal behaviour were observed: knocking, throwing, slamming (only males) and stacking (only males). Results indicated that O. rotundata constructed burrows with any shape in all types of sediment, from the backshore to the foreshore. Sand moisture decreased with distance from the sea, which was associated with an increase in burrow depth. Temporal variation had significant impact on burrow slope, so that the entrance branch of all burrow shapes was clearly steeper during the reproduction period in contrast to the same burrows created in the non-reproduction period.