Electric egg-laying: a new approach for regulating C. elegans egg-laying behaviour in a microchannel using electric field

C. elegans egg laying behavior and the associated cellular functions can be stimulated on-demand using electrical pulses in a microchannel.

The Relationship of Weight and Ovarian Development in Bombus terrestris L. Workers under Different Social Conditions

Egg-laying behaviour of bumblebee workers is highly flexible and influenced by the bees’ social status and social environment. In this study, the dependence of the starting time of ovarian development in Bombus terrestris workers was determined under four different social conditions. The purpose was to test the effect of group stimulation and the presence of a queen on ovarian development. The relationship between weight and the commencement of ovarian development in workers was also investigated. We created four test groups: (1) 8 callow workers with a queen, (2) 8 callow workers without a queen, (3) 1 callow worker with a queen, and (4) 1 callow worker without a queen. Mated and hibernated (freshly awoken) B. terrestris queens made up Group 1 and 3. There was no significant difference between the starting times of ovarian development in the experimental groups composed of 8 callow workers in queenright (9.81 ± 2.44 days) and queenless (9.53 ± 2.53 days) conditions. However, ovaries of workers confined singly with a queen started to develop significantly earlier (11.77 ± 3.30 days) than workers confined singly without a queen (14.70 ± 3.56 days). The observations indicate that the presence of a queen does not inhibit the ovarian development of workers. The Point-Biserial Correlation Coefficient between the starting of ovarian development in workers and their weight was −0.013. However, there was a positive correlation between the weight and the ovarian developmental status of workers in groups containing 8 workers.

Behavioural and genetic approaches to evaluate the effectiveness of deterrent marking by a parasitoid wasp

Some parasitoids deposit chemical signals after oviposition as an indication that the host has already been parasitized. This marking can deter subsequent conspecifics or one’s self from laying eggs in previously exploited hosts, thus reducing the risk of superparasitism. We investigated the egg laying behaviour of the parasitoid waspHyposoter horticola. In a laboratory experiment, we tested whether oviposition, post-oviposition marking, or both together deter subsequent oviposition by conspecifics. We then tested the effectiveness of the deterring mark under natural conditions using maternity assignment based on 14 polymorphic DNA microsatellite markers. The behavioural experiment showed that patch marking deters conspecifics from probing the host eggs, and oviposition deters those that probe from laying eggs in previously parasitized host clusters. These results were confirmed by the maternity assignment showing that under natural conditions, host egg clusters are primarily parasitized by a singleH. horticolafemale.

The effect of aryl hydrazono ester containing dipeptides (AHEDs) on mosquito egg-laying behaviour

Fifteen peptide derivatives were synthesized to study oviposition responses in mosquitoes at two different concentrations. AHED-6 showed the maximum oviposition attractant activity while AHED-13 exhibited the highest oviposition deterrent activity.