Birth synchrony and postnatal growth in Rhinolophus ferrumequinum (Chiroptera: Rhinolophidae) in two successive dry (2015) and wet year (2016) in a nursing colony in Kerend cave, western Iran

Abstract

AbstractSeasonality and synchrony of parturition and postnatal growth in Rhinolophus ferrumequinum have been studied in two consecutive years representing a typical dry (2015) and an extremely wet climatic event (2016) in Kerend cave, western Iran. In 2015, first pup was born on 20 May and by 10 days 85% of neonates were born. In the wet year, first pup was born on 26 May and by 10 days 56% of neonates were born. Synchrony of birth as defined by the clustering of births assessed by circular statistics showed that the angular variance in 2015 (S2 = 0.003) was significantly (p < .05) lower than in 2016 (S2 = 0.006). Multiple regression and generalized estimating equation indicate that the initial (y‐intercepts) forearm length and body mass were not significantly (p > .05) different between the 2 years, but the tests for parallelism shows a significant decrease in growth rates of body mass and forearm length in the wet year (p < .05). In 2016, juvenile bats began their first foraging flights at 24–28 days of age with higher but nonsignificant (p > .05) wing loading (7.71 ± 0.48 N/m2) compared with 2015 (7.65 ± 0.57 N/m2). Similarly, aspect ratio of 1‐day old neonates and juvenile bats in 2015 and 2016 did not show any significant difference (p > .05). Results of the present study suggest that R. ferrumequinum responded to prolonged precipitations and lower temperatures by delaying parturition, reducing birth synchrony and lowering postnatal growths.