Effects of parental age at mating on the fecundity and progeny sex ratio of Campoletis chlorideae, an endolarval parasitoid of the pod borer, Helicoverpa armigera

Abstract

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), commonly called gram pod borer, is a serious pest of pulse crops in India and damages chickpea (Cicer arietinum L). On average a 30% crop loss is reported. One of the potential natural enemies reported for its biological control is Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae), an idiobiont parasitic wasp that attacks second instar larvae of the pod borer. Male-biased sex ratios hinder efforts to mass release parasitic Hymenoptera for biological control by making the production of females costly. Parental age at time of mating is known to affect the progeny sex ratio in some Braconidae. In this view, we examined the reproduction and survival of the parasitoid C. chlorideae in the laboratory [22 ± 4°C, 70 ± 10% R.H. and 10:14 h light:dark photoperiod]. All the nine (i.e. 3 9 3) combinations of possible mating were made for males and females, being each of different age groups (0-12, 48-60 and 96-108 h old). Second instar larvae of the pod borer were reared on chickpea and exposed to mated females of different mating age group combinations. Results revealed that (a) newly emerged females (0-12 h old) mated to aged males yielded more progeny contrasted to the older females inseminated by newly emerged males (0-12 h old). This implies that increased maternal age at mating caused greater reduction in the progeny yield than that of paternal age; (b) the progeny sex ratio was lowest (0.344 ± 0.057) (mean ± SD) when parents mated just after emergence (0-12 h old). It became more and more male biased as parents were deprived of mate and was highest (0.666 ± 0.701) for 96-108 h old parents. The analysis of variance of the data shows that mate deprived males caused greater contribution in the production of sons, resulting a male-biased progeny sex ratio. Our conclusion indicate that newly emerged parasitoids (0-12 h old) are most fecund and should be used in rearing practices in order to enhance the progeny yield, particularly with respect to daughters.

Isolation and Characterization of Steinernema seemae Entomopathogens Against Helicoverpa armigera (Hubner) from North-Eastern Uttar Pradesh, India

“…Continued prospection for new EPN species or races that are infective for H. armigera is highly warranted [20][21][22] . The foremost critical factors include moisture, temperature, pathogenicity for the targeted insect etc 10 .…”

“…Initially, it was thought to be a great success and the people sighted a relief, but soon that they create more problems than were supposed to solve, or in other words, the insecticidal crisis proved to be a multifaceted one affecting society and the environment in diverse ways 9 . Secondly, biological control includes the utilization of natural organisms against harmful pathogens 10 . They seem to be environmentally friendly and don't seem to disturb the environment in any way i.e., environmental pollution such as soil, water, and air pollution is negligible 11 .…”

Thermal requirements and estimate number of generations of Palmistichus elaeisis (Hymenoptera: Eulophidae) in different Eucalyptus plantations regions

“…Smith, 1797) (Lepidoptera: Noctuidae), Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae) and T. arnobia (Bittencourt and Berti Filho, 2004a). Differences were also observed when comparing the cycle duration between these parasitoids and hosts at each temperature, indicating that both environmental factors and host species may interfere in the development of parasitoids (Bittencourt and Berti Filho, 2004a;Canto-Silva et al, 2005;Jacas et al, 2008;Golizadeh et al, 2008;Pandey and Tripathi, 2008;Pastori et al, 2008).…”

“…This is important because it allows the assumption that P. elaeisis can parasite and develops pupae in this pest at sites that presented similar temperatures. Therefore, the release of parasitoids in the field should be performed by looking at the thermal limits of the natural enemy for the establishment and efficiency to be higher (Jacas et al, 2008;Pandey and Tripathi, 2008).…”

Life History Evaluation of Ooencyrtus lucidus, a Newly Described Egg Parasitoid of Bagrada hilaris

“…Regulation of sex allocation with maternal age has been reported for other parasitoids [67][68][69]. Several physiological factors can result in the sex change and increase of male production by aged females, such as sperm depletion or senescence, reduced sperm viability, or weakened control of sperm release from spermatheca [70][71][72][73]. Sex ratio can also be affected by developmental mortality [74,75], superparasitism [76,77], or Wolbachia infection [78].…”