Spatiotemporal dynamics and plant-part preference patterns of the plant-visiting ants and the insect herbivores of sponge gourd plants

Authors Agarwal, Vivek Mohan; Rastogi, Neelkamal

Journal Journal of Asia-Pacific Entomology , 2009,2:12

Abstract Field investigations revealed a synchrony between daily and seasonal activity patterns of two Raphidopalpapests on the extrafloral nectary (EFN)-bearing sponge gourd, Luffa cylindrica (L.) plants. A similar patternwasrevealed in six of the most abundant plant-visiting ant species. The spatial activity patterns of the herbivores R.foveicollis and R. intermedia revealed a high frequency on the leaves (except, newly unfolded leaves) and thecorolla, but not on the bracts, bracteoles and the calyces of male/female buds and flowers. Young expandingleaves (leaf age class 2) had a significantly higher density of extrafloral nectaries (EFNs), as well as minimumleaf damage compared with the other leaf age classes. The density of EFNs was highest on the bracteoles andlowest on the leaves. In behavioural assays, ants demonstrated significantly greater preference for the 2-day oldbuds/newly opened leaves than the 2-day old intact unisexual flowers/corolla. Also, young, newly expandingleaves were preferred over young (unopened) and mature leaves. Thus, the higher density of EFNs atvulnerable plant sites, along with the visits of ants to such sites, may influence the spatiotemporal activitypatterns of the insect herbivores. These results provide support for the optimal defense hypothesis since theyshow that younger tissues and reproductive tissues may be getting better protection by the ant species.

Species covered 丝瓜(原变种) Luffa cylindrica