Eusocial insects are characterised by a reproductive caste differentiation such that egg-laying is restricted to a small number of queens. The majority of the colony members function as non-reproducing workers and gain indirect fitness by rearing the offspring of the reproductives. In primitively eusocial species, some workers can also get direct fitness by sneaking in some eggs in the presence of the queens, replacing the queens and becoming new queens, or initiating new nests. Here we aimed to understand the factors that permit some workers to gain direct fitness and alter the number of workers doing so, using the primitively eusocial wasp Ropalidia marginata. We transplanted 12 naturally occurring colonies into large laboratory cages where there was adequate space for the workers to leave their natal nests and initiate new colonies. We compared six control colonies that we provided with ad libitum food placed near the nest to six test colonies in which we hand-fed the wasps in addition to the ad libitum food. Wasps in test colonies consumed more food, showed more aggression, replaced their queens, and initiated new nests significantly more often than those in control colonies. When considering all 12 colonies, the rates of queen replacement and nest foundation were significantly positively correlated with food consumption rates. The additional nutrition gained by hand-fed wasps appears to help workers in test colonies to develop their ovaries and lay eggs, implying that they are nutritionally castrated in control colonies.

Feral pigeon Columba livia is one of the common bird species inhabiting in manmade structures though it may go for feeding away from nesting places. Cement concrete made buildings in use for Govt. departmental offices, educational Institutions, wear houses, sports complex, students hostels are mainly used by this species for nesting. In the current study it has been found adapted for use of readily available plant material to construct the nest. From observed three different types of total 133 nests 95 % were active and reused, 5 % were abandoned nests. Clutch size was 2 eggs per nest with overlapped breeding in 68.5 % nests. Safety of the nest and developing young, rich source of nesting material at selected nesting sites were the most preferred factors identified as main cause of expanding population of this pigeon. No predation of the eggs or young ones was recorded. Nuisance of faecal debris of this pigeon everyday in the main entrance corridor and office building verandas was most notable.