An optimized high quality male DNA extraction from spermatophores in open thelycum shrimp species

The crucial step of most of the current genetic studies is the extraction of DNA of sufficient quantity and quality.Several genomic DNA isolation methods have been described to successfully obtain male DNA from shrimp species.However,all current protocols require invasive handling methods with males for DNA isolation.Using Aristeus antennatus as a model we tested a reliable non-invasive differential DNA extraction method to male DNA isolation from spermatophores attached to female thelycum.The present protocol provides high quality and quantity DNA for polymerase chain reaction amplification and male genotyping.This new approach could be useful to experimental shrimp culture to select sires with relevant genetic patterns for selective breeding programs.More importantly,it can be applied to identify the mating pairs and male structure in wild populations of species as A.antennatus,where males are often difficult to capture.Our method could be also valuable for biological studies on other spermatophore-using species,such as myriapods,arachnids and insects.

Male nutritional status does not impact the reproductive potential of female Cnaphalocrocis medinalis moths under conditions of nutrient shortage

In addition to sperm,some accessory substances transferred to females during copulation act as nuptial gifts by passing on valuable nutrients in many insect species.The nutritional status of the males can thus have a great effect on the mating behavior,fecundity and even the longevity of females.However,little is known about the effect of male nutritional status on the female reproductive traits in migratory insect species,particularly when females experience nutrient shortage and have to choose between reproduction and migration.Here,Cnaphalocrocis medinalis,a migratory rice pest in Asia,was studied to explore this issue.Our results showed that in male moths fed with honey solution,their gonads had higher energy content than gonads of starved males,resulting in increased energy content of the bursa copulatrix of females after mating with fed males.Such females showed increased mating frequency,fecundity and longevity compared to females mating with starved males,indicating that male moths deliver nuptial gifts to females and improve their reproductive performance.However,when females were starved,only about 45%mated,with just a single copulation,regardless of male nutritional status.Starved females showed lower fecundity,and a longer pre-oviposition period(indicating a greater propensity to migrate),compared to fed females.However,copulation still significantly extended their longevity.These results suggest that starved females invest in migration to escape deteriorating habitats,rather than investing the nuptial gift to increased fecundity.Our results further our understanding of the reproductive adaptability of migratory insects under conditions of food stress.