Functional Morphology and Characters of five abundant species of Ladybirds (Coleoptera: Coccinellidae)

Functional morphology of five coccinellid species, viz.Coccinella septempunctata, Coccinella transversalis, Menochilus sexmaculatus, Propylea dissecta, and Hippodamia variegata, of the Coccinellini tribe (Coleoptera: Coccinellidae). These ladybirds prevalent arise in the agricultural fields, hence could be efficiently spotted by their characteristic elytral pattern and spots. However, we have dissected male and female genitalia and found significant differences at the species level. In males, paramere and median lobe while stylus and genital plate in females are exploitable to differentiate species exhibited by line-drawings.

DIVERSITY OF PREDACEOUS COCCINELLID BEETLES (COLEOPTERA: COCCINELLIDAE) IN UTTARAKHAND, NORTH INDIA

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

Limb regeneration modulates reproductive attributes in ladybirds: A case study in Propylea dissecta and Coccinella septempunctata

ABSTRACTRegeneration is the capability to regrow or repair the lost or injured body parts. In holometabolous insects, the adult development undergoes through larval and pupal stages. Literature revealed that the limb regeneration has various impact on different life traits of organisms. In the present study, we investigated limb regeneration of two different sized ladybirds affect their life attributes. Fourth instar larvae of small ladybird Propylea dissecta and the large ladybird Coccinella septempunctata were taken from the laboratory stock and were given an ablation treatment, viz. forelegs of larvae were amputated at the base of the coxa. Amputated larvae were observed until the adult emergence. Emerged adults were grouped in different categories on the basis limb regeneration i.e. regenerated adults (incomplete regenerated in case of P. dissecta), unregenerated, and normal (control) adults. These adults were kept in different mating treatments. The unregenerated adults of both the ladybirds took more time to commence mating with shorter copulation duration and reduced fecundity and percent egg viability. Thus, it can be concluded that regeneration ability modulates the life attributes of the ladybirds irrespective of their body size.

The Capacity for Limb Regeneration During Metamorphosis is Broadly Conserved in the Coccinellidae

A standardized laboratory procedure tested the limb regeneration abilities of 18 populations (16 species) of lady beetles which were then scored, relative to unoperated controls, based on survival, the proportion regenerating the limb completely or partially, and the magnitude of developmental costs (delayed development, reduced body size) associated with limb ablation. Newly molted fourth instar larvae each had a single foreleg amputated at the base of the femur. All species except Propylea dissecta (Mulsant) showed some complete limb regeneration, with limb regeneration index (LRI) scores ranging from 0.025 to 0.905 out of a possible 1.00 (mean = 0.598). Eriopis connexa Germar, an aphidophagous neotropical species, scored the highest. Widely distributed species that dominate agricultural habitats all scored above 0.75, and the only herbivore, Henosepilachna argus (Geoffroy), scored second from lowest. Prolonged pupal development was the most common cost, occurring in nine species, and correlating negatively with regeneration. Taxonomic distance between species correlated with regeneration, but explained <5% of variation; principal component analysis indicated that the LRI was the main factor distinguishing species. We infer that this capacity is conserved, not because of any adaptive advantage conferred, but because the genes responsible are normally activated during pupal development to generate the adult body plan and reconstitute appendages with direct correspondence to larval progenitors. However, good regeneration capacity was associated with the ecological success of the species. In general, broad geographic distribution, guild dominance, polyphagy, interspecific competitiveness, phenotypic flexibility, and invasiveness were characteristics generally shared by species with high levels of regeneration.

Impact of female mating status and female familiarity with remating interval on the reproductive success of Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae)

Remating rate is a fundamental parameter that acts on disease transmission, sexual dimorphism, and the rate of evolution of species. Recent studies have indicated that sperm production can be costly. It is thus likely that males may tailor their sperm expenditure according to female mating status and the remating interval between successive matings. In this study, we investigated the effects of male remating interval, female mating status and familiarity of females in the ladybird beetle Propylea dissecta (Mulsant). Ten-day-old adults were allowed to mate and, post disengagement, these adults were exposed to second mating opportunities, either immediately after the first mating, or 6, 18 or 24 h later. To assess the effect of female mating status, the males were subjected to mating with virgin and mated females. Similarly, for assessing the effects of female familiarity, males were subjected to mating with either familiar or unfamiliar females. With increasing remating interval individuals mated for longer, resulting in higher fecundity. Percent egg viability increased with increased remating interval and was highest at 24 h. Mated and unfamiliar females were found to be more fecund than virgin females. Mated females produced a higher number of viable eggs than virgins, suggesting that multiple mating and promiscuity are essential for maximizing the reproductive success of both sexes.

Are the effects of hunger stage-specific? A case study in an aphidophagous ladybird beetle

Food availability is a fundamental factor determining an animal's potential fitness. Carry-over effects of food limitation from development to adulthood are known to influence reproduction, ageing, and tolerance to stress. We have examined the effect of stage-specific variation (before adult emergence or pre-emergence, post-emergence and post-mating) in food availability in Propylea dissecta (Mulsant). Larvae were reared separately on two different pre-emergence food regimes (abundant or restricted) until pupation. Newly emerged adults were further split into two groups and placed on abundant or restricted post-emergence regimes. After mating, females were split and reared on any one of two post-mating regimes. The results revealed that: (i) time to commence mating declined with increased food availability in pre- and post-emergence stages, (ii) mating duration increased with food availability post-emergence, (iii) highest reproduction output was observed in individuals who had abundant food pre- and post-emergence. However, food availability at the time of oviposition also had a strong influence on fecundity. Solo bouts of scarcity, regardless of which stage suffered them, were effectively managed in at least two of the three stages (pre-emergence, post-emergence, post-mating) had abundant food.

Biology, Predatory Potential, Life Table, and Field Evaluation of Propylea dissecta (Coleoptera: Coccinellidae), Against Lipaphis erysimi (Hemiptera: Aphididae) on Broccoli

Propylea dissecta (Mulsant) (Coleoptera: Coccinellidae) is one of the most promising ladybird beetle against many sucking pests. Predation rates, developmental biology, life table, and field assessment of this ladybird were examined against mustard aphid, Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae), on broccoli. Data on the life history were collected at 23 ± 1°C and 70 ± 1% RH and were evaluated using the two-sex, age-stage life table. Results showed that the two-sex, age-stage life table-based net reproductive rate (R0) was 11.264 ± 6.197 offspring. The adult females lived longer (33.8 ± 2.356 d) than the adult males (32.2 ± 0.841 d). The fourth instar consumed most of L. erysimi (113.97 ± 5.76) compared to the other larval stages of the predator. Male (1,821) and female (2,673) consumed more aphids than larvae. The net consumption rate was 741.78 ± 89.91 aphids. Other aphidophagous predators such as Coccinella septempunctata L., Micraspis discolor (F.), Coccinella transversalis (F.), and syrphid (Diptera: Syrphidae) were also noted in broccoli. Our research showed that inoculative release of 150 or 200 adults per 1,000 m2 for two times on broccoli achieved a significant decrease in aphids L. erysimi and Brevicoryne brassicae L. (Hemiptera: Aphididae) (>95%). The release rate of 150 adults per 1,000 m2 for two times may, therefore, be recommended to manage the aphid population on broccoli.