Evaluation of darwin's fecundity advantage hypothesis in parthenium beetle,zygogramma bicoloratapallister

Abstract

In the Parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), variation in body size exists between and within the sexes. The females are larger than the males. Darwin (1874) proposed the fecundity advantage hypothesis, i.e. large sized female produce more progeny, with subsequent studies supporting as well as refuting the hypothesis. Thus, in order to evaluate whether this hypothesis stands in Z. bicolorata we performed experiments to investigate the role of body size in influencing: (i) assortative mating, (ii) reproductive attributes, and (iii) growth, development and survival of offspring. It is the first attempt in this beetle. We found that size influenced assortative mating, reproductive output and offspring fitness. Larger males and females were preferred as mates over smaller ones. The pairs having larger adults as mates had higher fecundity while the egg viability was influenced by the male size only. The offspring of larger parents had fast development and higher survival indicating thereby possible better nutrient allotment by the female and supply of accessory gland proteins by the male in addition to better quality of genes.

Effect of photoperiod on slow and fast developing individuals in aphidophagous ladybirds, Menochilus sexmaculatus and Propylea dissecta (Coleoptera: Coccinellidae)

“…As fast developing females were larger in size than slow developing females, hence have higher fecundity (Brown & Mauer, 1986;Charnov & Ernest, 2006;Davidowitz, 2008). Larger females lay more and bigger eggs that facilitate faster development (Stearns, 1992;Cloutier et al, 2000;Garcia-Barros, 2000;Katvala & Kaitala, 2001;Roff, 2002;Omkar & Afaq, 2013). This result is consistent with the report of Skorping (2007) that fast developing T. circumcincta were evolved with higher fecundity but poorer survival than the slow developing ones.…”

Testing the fecundity advantage hypothesis with Sitobion avenae, Rhopalosiphum padi and Schizaphis graminum (Hemiptera: Aphididae) feeding on ten wheat accessions

“…These life-history traits are generally used to evaluate the adaptability, phenotypic plasticity, and population dynamics of insect response to changes in environmental conditions and the resistance of host crop accessions to insects 12 13 14 15 16 17 18 19 20 21 22 . The fecundity advantage hypothesis, proposed by Darwin in 1874, suggests that large females have an evolutionary advantage over their smaller counterparts because they produce more offspring 23 24 . Ecologists use the correlations between various biological parameters to establish and interpret the relationships between individual life-history traits and population dynamics; correlations between F and other biological parameters have been extensively and exhaustively studied 1 2 3 4 5 6 7 8 9 10 11 24 25 26 27 28 29 30 31 .…”

“…Positive correlations between F and body weight or growth rate have been found in more than 60 insect species in eight orders—Coleoptera, Lepidoptera, Homoptera, Diptera, Ephemeroptera, Heteroptera, Hymenoptera, and Trichoptera 24 25 26 27 28 29 30 31 . Fenchel (1974) found a general correlation between r m and average body weight in animals 31 .…”

Lethal and Sublethal Effects of Insecticides Used in Cotton on Harmonia Axyridis

“…Thus, the reduced weight of adult males may have been due to these effects of the insecticide, leading to reduced food consumption of H. axyridis. Although only the weight of males changed, this may explain the reduction in egg viability because males with higher weight may supply a more sperm, oviposition stimulants, and other nutrients during copulation than smaller males (Omkar and Afaq, 2013;Singh et al, 2019). According to Almasi et al (2013), pymetrozine caused close to 40% mortality of third-instar larvae of the ladybug Hippodamia variegate (Goeze) (Coleoptera: Coccinellidae).…”