Compatibility of entomopathogenic nematodes with insecticides against the cabbage white butterfly, Pieris rapae L. (Lepidoptera: Pieridae)

Background Compatibility of entomopathogenic nematodes (EPNs) with insecticides is a crucial mainstay of integrated pest management (IPM) programs. This study was designed to evaluate the joint action of EPN species and insecticides when employed to deter 3rd and 4th larval instars of cabbage white butterfly, Pieris rapae L. (Lepidoptera: Pieridae) under laboratory conditions. EPNs [Steinernema carpocapsae (All strain), S. feltiae (Filipjev), Heterorhabditis bacteriophora (HP88), and H. bacteriophora (Ar-4)], at concentrations of 50, 100, and 125 IJs/larva, were tested with 3 insecticides (lambda-cyhalothrin, emamectin benzoate, and indoxacarb) at LC25 and LC50 values. Additionally, expression profiles of 2 detoxification genes (CYP6AE120 and PrGSTs1) when the 4th instar larvae were treated by H. bacteriophora (HP88) and lambda-cyhalothrin were examined. Results Data indicated that statistically significant mortality of 2 larval instars of P. rapae was observed in vitro among EPN species and pesticide concentrations. At concentration of 50 IJs/larva, LT50 values were 2.385 and 3.92 days for S. carpocapsae (All strain) and H. bacteriophora(Ar-4), respectively, on 3rd instar larvae; also, these values were 3.506 and 3.107 days for S. feltiae and H. bacteriophora (Ar-4), respectively, on 4th instar larvae Lambda-cyhalothrin was the most toxic insecticide, followed by emamectin benzoate and indoxacarb at LC25 and LC50, respectively. An additive effect was observed between EPN species with LC25 and LC50 of the tested insecticides, except for lambda-cyhalothrin at LC50 with H. bacteriophora (Ar-4), and indoxacarb, with all EPNs showing antagonistic effects on mortality of 3rd instar larvae after 3 days post-treatment. The interaction between the tested pesticides at LC25 and LC50 and EPN species, showed an additive effect, excluding lambda-cyhalothrin at LC25 with S. carpocapsae (All strain) and LC25 of indoxacarb with H. bacteriophora (Ar-4), which showed potentiation effects. The interaction of S. feltiae (Filipjev) with tested insecticides at LC50 exhibited an antagonistic effect on the mortality of 4th instar P. rapae larvae after 3 days post-treatment. The expression of both CYP6AE120 and PrGSTs1 was significantly up-regulated with lambda-cyhalothrin, followed by H. bacteriophora (HP88) compared to control. Conclusions The findings suggested that combining EPNs and the pesticide concentrations can be a practical strategy for managing P. rapae and could pave the way to using new control technologies in protecting organic farm vegetables from lepidopteran pests.

Determination Of Effective Parasite-Entomofag Species In The Management Of The Number Of Family Representatives In Pieridae

The article covers studies that cabbage white butterfly is considered a dangerous pest common in vegetable crops and can cause great harm by feeding on more than 10 species of cabbage crops. Also, such pests as cabbage white butterfly, turnip white butterfly and rap white butterfly have been covered in scientific research to prevent the death of up to 60-65% of the crop in cabbage, turnip, radish and radish crops in mammal conditions.

In search of an honest butterfly: sexually selected wing coloration and reproductive traits from wild populations of the cabbage white butterfly

Sexual selection is an important and well-studied topic and is central to many theories on mate selection and individual behavior. Relatively little is known about the impacts that human-induced rapid environmental change are having on secondary sexually selected characteristics. In particular, we lack a clear understanding of the effects of the introduction of once-limiting nutrients to wild populations. Honest signals function as an indicator of mate quality when there are differences in nutrient acquisition and allocation to secondary traits. We used the cabbage white butterfly, Pieris rapae (L.), to investigate differences in color and testes size as an index of reproductive potential. We collected individuals from four sites in California and Nevada to capture variation among areas with high and low cropland and potential nitrogen availability. Differences in mean testes size among sites raise the possibility that individuals from sites surrounded by high agricultural areas have smaller testes than individuals from less agriculturally-developed areas. Coloration variables and testes size were positively associated, consistent with the hypothesis that nitrogen-based coloration in the cabbage white is an honest mating signal. However, variation among sites in that relationship suggests complexities that need further exploration, including the possibility that the signal is not of equal value in all populations. Thus these results advance our understanding of complex relationships among human-induced environmental change and sexual selection in the wild.

Global invasion history of the world’s most abundant pest butterfly: a citizen science population genomics study

A major goal of invasion and climate change biology research is to understand the ecological and evolutionary responses of organisms to anthropogenic disturbance, especially over large spatial and temporal scales. One significant, and sometimes unattainable, challenge of these studies is garnering sufficient numbers of relevant specimens, especially for species spread across multiple continents. We developed a citizen science project, “Pieris Project”, to successfully amass thousands of specimens of the invasive agricultural pest Pieris rapae, the small cabbage white butterfly, from 32 countries worldwide. We then generated and analyzed genomic (ddRAD) and mitochondrial DNA sequence data for these samples to reconstruct and compare different global invasion history scenarios. Our results bolster historical accounts of the global spread and timing of P. rapae introductions. The spread of P. rapae over the last ∼160 years followed a linear series of at least four founding events, with each introduced population serving as the source for the next. We provide the first molecular evidence supporting the hypothesis that the ongoing divergence of the European and Asian subspecies of P. rapae (∼1,200 yrBP) coincides with the domestication of brassicaceous crops. Finally, the international success of the Pieris Project allowed us to nearly double the geographic scope of our sampling (i.e., add >1,000 specimens from 13 countries), demonstrating the power of the public to aid scientists in collections-based research addressing important questions in ecology and evolutionary biology.Non-technical summaryWe provide genetic evidence that the success of the small cabbage white butterfly—its rise to one of the most widespread and abundant butterflies on the planet— was largely facilitated by human activities, through the domestication of its food plants and the accidental movement of the butterfly by means of trade and human movement (migration). Through an international citizen science project—Pieris Project—people from around the world helped to unravel the global invasion history of this agricultural pest butterfly by collecting samples for DNA analysis. The success of this citizen science project demonstrates the power of the public to aid in collections-based research that address important questions related to ecology and evolutionary biology.