No abstract

The ability to recognize kin is a well-established behavior across several animal phyla including insects. A laboratory experiment was designed to find out whether adults of an aphid-biocontrol agent, Propylea dissecta (Coleoptera: Coccinellidae) may avoid consuming their own eggs in prey scarcity in the presence of unrelated conspecific eggs. For the purpose, starved parent ladybirds were provided with their eggs and unrelated conspecific (alien) eggs in the absence of their natural prey (aphids). The predatory/ avoidance behavior of the parents towards alien-eggs and their eggs was recorded. The adult male of P. dissecta had lesser food demand than the female and consumed significantly lesser (0.7±0.20) kin eggs than the alien eggs (2.8±1.89). Similarly, the adult female cannibalized significantly lesser number of kin eggs (1.6±0.209) than the alien-eggs (3.5±0.15). Seemingly, both the parents had recognized their eggs and refrained from consuming them. This could be a strategy adopted by the parents to conserve their gene-pool and to further protect it by consuming the heterospecific eggs of potential enemies (alien eggs) in prey scarcity. This insurance of their gene-pool could benefit these parents by conserving their genetic lines.

We investigated mating reluctance with relatives and its influence on the quantitative progeny and its fitness using a predatory ladybird, Propylea dissecta. For this purpose, we compared mating behaviour, mating duration and post-mating response in the form of fecundity, egg-viability, progeny-development, weight and fitness when mating occurred between relatives (father-daughter, mother-son, and siblings) with unrelated ladybird couples. Females of P. dissecta, particularly those belonging to earlier (mother) or later generation (daughter) exhibited strong mating reluctance than those of same generation (sibling) relatives. This reluctance was lacking in unrelated female ladybirds. A similar pattern was reflected in the mating duration and post-mating responses, as unrelated females mated for the longest duration with high fecundity, oviposition period and percentage of egg viability. Furthermore, the first progeny suffered the implication of mating with relatives in the form of delayed development, lighter developmental stages and reduced fitness with those experiencing maximum whose parents were not of the same generation. These parameters were optimal in the progeny of unrelated parents. These results alarm the process of mass-rearing, where the ladybirds are augmented giving no consideration to the parental line and allowing mating between relatives, which may result in inbreeding depression, thereby deteriorating the quality of progeny and impeding the biocontrol programmes.

An extensive survey was conducted to explore the biodiversity of predaceous ladybirds (Coleoptera Coccinellidae) and to evaluate their biodiversity indices from five zoogeographical habitats in Uttarakhand, North India. A total of 1883 ladybird specimens with 18 species were recorded belonging to three sub-families (Chilocorinae Scymninae Coccinellinae), three tribes (Platynaspidini Scymnini Coccinellinae) and thirteen genera. Seven-spotted ladybird, Coccinella septempunctata (Linnaeus, 1758) was highly abundant (32.13% of total frequency), followed by Menochilus sexmaculatus (Fabricius, 1781) (23.69%). Platynaspis saundersi (Crotch, 1874) was the least abundant ladybird species. Shannon Wiener's index was the highest (2.1012) for Chamoli region exhibiting it as most species diverse habitat, which is the reason for the high pooled SW index of 2.0349 from Uttarakhand. Low Simpson's diversity index (D) was evaluated from Uttarkashi (0.1720) and Chamoli (0.1758) revealing a relative increase in coccinellid diversity from other habitats. Margalef index measuring the species richness was the highest in Chamoli (5.0634). High Pielou's evenness Index was evaluated from Uttarkashi and Chamoli suggesting that species are the most evenly distributed in these habitats. Sorenson's Index was highest (0.7368) between Nainital and Almora, which reveals maximum similarity in the species belonging to these two habitats. Similar habitats in altitude and climate have high similarity index, which suggests aggregation of ladybird species is highly dependent on climatic conditions and altitude.

A field survey was conducted to explore the diversity of predaceous ladybird beetles (Coleoptera: Coccinellidae) by sampling adults and larvae from five geographical habitats of Uttarakhand, North India. As a result, eighteen predaceous ladybird beetle species were identified belonging to 15 genera and 3 subfamilies: Chilocorinae, Coccinellinae, and Scymninae. These species were: Platynaspis saundersi, Adalia hexaspilota, Alloneda dodecaspilota, Calvia albida, Menochilus sexmaculatus, Coccinella septempunctata, Coccinella transversalis, Harmonia eucharis, Harmonia sedecimnotata; Hippodamia variegata, Illeis cincta, Illeis confusa, Micraspis discolor, Oenopia sauzeti, Propylea dissecta; Propylea luteopustulata; Palaeoneda auriculata and Scymnus posticalis. Of these, six species ladybird beetles are the first time reported from Uttarakhand. Their distinctive characters, distribution, host plant-prey range, active period, and ecological importance have been described. A few of these species may be potentially utilized as biological agents to control many phytophagous insect pests of agriculture and horticulture crops. A disparity was observed in the ladybird-abundance, as both the number of individuals of ladybirds and their frequency in the population differed significantly. The dominance of a few ladybird beetles, particularly C. septempunctata, M. sexmaculatus, C. transversalis and H. variegata was confirmed by the low value of Simpson’s Dominance Index (0.1903) further indicating the disparity in the populations of different ladybird species in a community