Understanding the insect foragers and their foraging behaviour on the mangrove Bruguiera cylindrica (L.) Bl. (Rhizophoraceae)

Abstract

The breeding system of Bruguiera cylindrica, its associated foragers, and their foraging activity were carried out from 2018−2021 in the mangroves of Chettuva, of Thrissur district in the State of Kerala. The flowering of B. cylindrica commences during October and found to cease by the end of January. Bagging experiment revealed that they prefer xenogamous mode (88%) of reproduction though they had a small percentage of fruit set via autogamy (16%).Thirty five species of insects were recorded on the flowers of B. cylindrica. Among them, eleven species were foraging on the flowers of B. cylindrica. The most abundant foraging species were Chrysomya megacephala, Apis florea and Campsomeriella collaris.

C. megacephala had significantly higher visitation rate (7.52 flowers/min) whereas Dolichopus sp. recorded significantly higher handling time (11.71 s). The highest pollen load was obtained from Chrysomya megacephala (161.50 ± 4.90). The peak foraging activity was recorded during 10.00 hrs. − 11.00 hrs. in the morning and 16.00 hrs. − 17.00 hrs. in the evening. The findings of the study complement the role and significance of insect foragers in the breeding of mangrove species.