In laboratory and garden experiments, we tested for the existence of adaptive patterns of oviposition and larval behaviour regarding group size in the gregarious tortoise beetle Chelymorpha varians Blanchard (Coleoptera: Chrysomelidae: Cassidinae) on its host plant Calystegia sepium L. (Convolvulaceae). Specifically, we addressed the following questions: (i) Which is the more frequent egg cluster size? (ii) Does cluster size fully predict larval group size? (iii) Are newborn larvae attracted or repelled to conspecific groupings? and (iv) Which is the group size associated with enhanced larval development and adult mass? We found that the mean cluster size was 21.4 eggs. Egg hatch time was significantly shorter in larger clusters. A regression analysis of larval group size against cluster size showed non-significant results. Thus, original cluster size did not totally determine the larval group size. The mean larval group size was 17.1. Choice tests in an experimental arena showed that larvae clearly preferred leaves of a host plant rather than moistened papers, and that larvae preferred a small group of conspecifics (four larvae per leaf) over larger groups (12 or 20 larvae). Empty leaves of the host plant showed an intermediate level of preference. Development time and beetle performance (adult mass) were affected by larval group size. Larvae in the smallest group (one per leaf) took four more days to attain adulthood than larvae in the larger groups (12 and 20 larvae). Adult C. varians reared in the 12-larvae group were significantly larger than those reared at the other densities. Comparison of patterns across experimental groups, excluding the 12-larvae group, showed a tendency for a greater final mass with slower developmental rate.
Insects are attracted to plants by visual and olfactory cues. The quinoa moth, Eurysacca melanocampta Meyrick (Lepidoptera: Gelechiidae), is the main insect pest of the quinoa crop, Chenopodium quinoa Willd. (Chenopodiales: Chenopodiaceae), in the southern Peruvian Andes, causing grain yield losses. The aim of this study was to investigate the behavioural response of adult quinoa moths to olfactory stimuli. Specifically, the objectives of this study were: 1) to determine the capacity of E. melanocampta adults of searching for quinoa plants using plant olfactory cues; 2) to determine the preference of E. melanocampta females for the odours derived from two varieties of quinoa: Amarilla de Marangani and Blanca de Junín; and 3) to assess the attraction of male quinoa moths to E. melanocampta females and the host plant in olfactometric bioassays. Adults preferred quinoa plant odour sources in choice tests when distilled water was used as a control (P < 0.0001). Females were more attracted to the Blanca de Junín variety than to Amarilla de Marangani variety (P < 0.05). Males were more attracted to the odour derived from females than to the volatile compounds from plants (both varieties) or to the odour blend derived from plants plus females together. The level of attraction of males towards females is negatively affected by the presence of the quinoa plants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.