The effects of temperature on the development of the moth Athetis lepigone, and a prediction of field occurrence

Age-Stage, Two-Sex Life Table of Atractomorpha lata (Orthoptera: Pyrgomorphidae) at Different Temperatures

Atractomorpha lata Motschoulsky (Orthoptera: Pyrgomorphidae) has recently emerged as an important agricultural pest in China. Understanding the impact of temperature on its developmental period is crucial for predicting its population dynamics. This study systematically observed the biological characteristics of A. lata at five temperatures (16, 20, 24, 28, and 32 °C) using the age-stage, two-sex life table method. The effects of temperature on the developmental period, survival rate, and fecundity of A. lata were studied using fresh bean leaves as host. The results demonstrated that as temperature increased from 16 °C to 32 °C, the developmental period, preadult time, adult longevity, adult preoviposition period (APOP), and total preoviposition period (TPOP) significantly decreased. The developmental threshold temperatures for various stages were calculated, ranging from 10.47 °C to 13.01 °C, using the linear optimal method. As temperature increased, both the intrinsic rate of increase (r) and the finite rate of increase (λ) also increased, while the mean generation time (T) decreased. The optimal values of the net reproductive rate (R0 = 54.26 offspring), gross reproductive rate (GRR = 185.53 ± 16.94 offspring), and fecundity (169.56 ± 9.93 eggs) were observed at 24 °C. Similarly, the population trend index (I) for A. lata peaked at 24 °C (61.64). Our findings indicate that A. lata exhibits its highest population growth rate at 24 °C, providing a scientific basis for predicting its population dynamics in the field.

The chromosomal-scale genome sequencing and assembly of Athetis lepigone

Athetis lepigone is an emerging highly polyphagous insect pest reported to cause crop damage in several European and Asian countries. However, our understanding of its genetic adaptation mechanisms has been limited due to lack of high-quality genetic resources. In this study, we present a chromosomal-level genome of A. lepigone, representing the first species in the genus of Athetis. We employed PacBio long-read sequencing and Hi-C technologies to generate 612.49 Mb genome assembly which contains 42.43% repeat sequences with a scaffold N50 of 20.9 Mb. The contigs were successfully clustered into 31 chromosomal-size scaffolds with 37% GC content. BUSCO assessment revealed a genome completeness of 97.4% with 96.3 identified as core Arthropoda single copy orthologs. Among the 17,322 genes that were predicted, 15,965 genes were functionally annotated, representing a coverage of 92.17%. Furthermore, we revealed 106 P450, 37 GST, 27 UGT, and 74 COE gene families in the genome of A. lepigone. This genome provides a significant and invaluable genomic resource for further research across the entire genus of Athetis.

Effect of Different Plants on the Growth and Reproduction of Thrips flavus (Thysanoptera: Thripidae)

Simple Summary

Thrips flavus Schrank (Thysanoptera: Thripidae) is a worldwide phytophagous pest in Palearctic Asian and European countries. T. flavus feeds on a wide spectrum of host plants. Thus, understanding its host plant preferences is important for pest control. We tested the development duration, population parameters, and population growth of T. flavus on five species of plants. The intrinsic rate of increase and fecundity was the highest on Cucumis sativus, followed by Glycine max and Capsicum annuum. However, Solanum melongena and Brassica rapa var. glabra were not suitable host plants. These results help to improve our understanding of the population dynamics of T. flavus and should lead to positive measures to control thrips in the field.

Abstract

Host plants play an important role in affecting insect development and reproduction. Understanding the host plant preferences is important for pest control. Thrips flavus Schrank (Thysanoptera: Thripidae) is a worldwide phytophagous pest in Palearctic Asian and European countries. We used a life table analysis to study the development duration, population parameters, and population growth of T. flavus on five plant species, including Solanum melongena (Solanaceae), Capsicum annuum (Solanaceae), Glycine max (Leguminosae), Brassica rapa var. glabra (Cruciferae), and Cucumis sativus (Cucurbitaceae). The results showed that T. flavus can survive and reproduce on Cu. sativus and G. max, which were two potentially suitable host plants. T. flavus preferred to oviposit on Cu. sativus with a shorter duration of development (17.8 days) at 25 °C. Therefore, the host plant was an important factor influencing the development and fecundity of T. flavus populations. These results will improve our understanding of the population dynamics of T. flavus and facilitate the development of more scientific and efficient measures to control thrips.

Effect of Temperature on the Development, Survival, and Fecundity of Heliothis viriplaca (Lepidoptera: Noctuidae)

Heliothis viriplaca (Hüfnagel) (Lepidoptera: Noctuidae) is worldwide an important economic pest of major agricultural crops. The effect of temperature on the biology, in particular the duration of the different developmental stages, of this insect pest was examined. The development, survival, and fecundity of H. viriplaca at five different temperatures (22, 25, 28, 31, and 34°C) were investigated, and experimental population life tables calculated. The results show that the developmental time of larvae, pupae, pre-oviposition, adults, and the entire generation decreases with increasing temperature. Larvae emerged fastest from the eggs at 28°C. The percentage of larvae that reached the seventh instar stage was 32.69, 38.60, 19.67, 3.61, and 20.88% at 22, 25, 28, 31, and 34°C, respectively. The developmental threshold temperature of the eggs, larvae, pupae, pre-oviposition and total pre-oviposition period was 10.53, 12.34, 5.60, 11.47, and 10.01°C, respectively. The effective accumulative temperature was 42.90, 239.68, 309.19, 77.72, and 767.64 degree-days, respectively. The population trend index (I) and the intrinsic rate of increase (r) of H. viriplaca were the highest at 31°C (133.97 and 0.12 d-1, respectively). The results of this study may be useful for predicting the population dynamics of H. viriplaca and thus provides information on this important insect pest that may assist in its management.