Changes in body size and fertility due to artificial and natural feeding of laboratory common bed bugs (Heteroptera: Cimicidae)

Rearing common bed bugs (Cimex lectularius L.) and other hematophagous insects is essential for basic, medical, and pest-control research. Logistically, acquiring fresh blood can be a challenge, while biologically, the eventual effects of different rearing and blood preparation protocols on bed bug genotype and phenotype pose a risk of biased research results. Using bed bug populations that are either bat- (BL) or human-related (HL), we tested the short- and long-term effects of rearing bugs on live bats or human volunteers, or artificially on CPDA (citrate phosphate dextrose, adenine)-treated blood, measuring meal size, body size, and fertility. We found that artificial feeding did not affect meal size compared with feeding on natural hosts. Long-term rearing across many generations of HL on CPDA-preserved blood led to reduced body size and fertility compared with populations reared on human volunteers. Blood preservatives increased the proportion of sterile eggs even after a single feed. Finally, our results indicated that laboratory reared bed bugs were smaller, regardless of the blood source, than wild bugs. Similar effects of artificial feeding or laboratory rearing alone should be considered in future studies using bed bug cultures to choose an appropriate rearing protocol. With regard to switching between bat and human hosts, HL took smaller meals and BL had lower fertility when fed on bats than when fed on humans. We attribute these results to methodological constrains, specifically the inconsistency of bat feeding, rather than to host specialization. Nevertheless, BL can be easily reared using human blood and artificial feeding systems.

Effects of Delayed Mating on the Reproductive Performance of Henosepilachna vigintioctopunctata (F.) (Coleoptera: Coccinellidae)

Simple Summary

In many Asian countries, Henosepilachna vigintioctopunctata (F.), is seriously harmful to Solanaceae vegetables. With the popularization of green agriculture and the improvement in people’s living standards, biological pest control may become the mainstream. The artificial release of sex pheromones and other methods to delay insect mating, thus affecting population abundance, is an important part of biological control. We took H. vigintioctopunctata collected from Jingzhou, Hubei Province, China, back to the laboratory to establish an experimental population to study the effect of delayed mating on its reproductive behavior. The negative effects on reproduction and changes in population life table parameters, such as net reproductive rate, intrinsic and finite rates of increase, doubling time, and mean generation time, could be estimated by the treatment of delayed mating of males and females, which could be useful for providing important information for pest control in the future.

Abstract

Henosepilachna vigintioctopunctata (F.) is a serious pest of numerous solanaceous crops in many Asian countries. The purpose of this study was to clarify the effects of delayed mating on mating success, fecundity, fertility, pre-oviposition period, oviposition period, adult longevity, and population life table parameters (including net reproductive rate, intrinsic and finite rates of increase, doubling time, and mean generation time) of H. vigintioctopunctata. Beginning three days after emergence for both sexes, mating was delayed an additional 0, 2, 4, 6, or 8 days. We compared the data when mating was delayed for males only with the data when mating was similarly delayed for females only. Reproductive and life table parameters were calculated from the two data sets and compared. The results showed that the preoviposition and oviposition period of adults was significantly reduced by delayed mating, while the preoviposition period was not significantly different in adults mated at older ages. The mating success rate, fecundity, and proportion of hatching eggs decreased with increasing mating age. Longevity was not affected by the age at mating. Mating delay also affected the life table parameters of H. vigintioctopunctata, with a similar trend observed in the net reproductive rate and intrinsic and finite rates of increase, all of which decreased gradually as the number of delay days increased. The population doubling time increased with increases in mating age. The results also showed that delayed mating was an effective measure to consider in controlling H. vigintioctopunctata. It is hoped that our data will provide a scientific basis and contribute technical guidance for forecasting and integrated management of this pest.

Mating Delay Reduces Reproductive Performance but not Longevity in a Monandrous Moth

Age at mating is one of the most important factors that affect mating success and reproductive fitness in insects. The present study investigated how the age of the two sexes at mating determined mating success, reproductive fitness and longevity in Phauda flammans (Walker) (Lepidoptera: Phaudidae), a serious pest of Ficus spp. trees in South and Southeast Asia. The study may provide basic knowledge for the development of mating disruption programs using sex pheromones to control this pest. The species is monandrous and its adults live for only 4-5 d. We show that delayed mating significantly lowered mating success in both sexes, with males being more severely affected than females. Mating delay also reduced reproductive outputs of both sexes but females were more negatively affected than males. We did not find any effect of delayed mating on longevity of either sex. Our findings suggest that mating disruption with sex pheromones can be an effective method to delay mating in P. flammans, reducing reproductive success and thus limit population growth.