Seasonal Population Patterns of a New Scale Pest, Acanthococcus lagerstroemiae Kuwana (Hemiptera: Sternorrhynca: Eriococcidae), of Crapemyrtles in Texas, Louisiana, and Arkansas.1

The crapemyrtle bark scale, Acanthococcus lagerstroemiae, is an invasive scale insect pest of crapemyrtles. Crawler populations were monitored using double-sided sticky tape on established crapemyrtle trees in Tyler (TX), Huntsville (TX), Dallas (TX), College Station (TX), Shreveport (LA), and Little Rock (AR) from 2015 - 2017 to determine crawler activity and determine if degree-day models could predict the first peak in crawler activity. Difference in crawler densities on upper and lower branches of trees was also determined by using double-sided sticky tapes. The first peak in crapemyrtle bark scale crawler activity was between March 26th and May 22nd across all locations and years, with multiple subsequent peaks per season frequently found, suggesting multiple generations. Using the average date (May 2nd) to predict the first peak crawler activity resulted in the lowest variance and was subsequently considered a better predictor compared to any degree-day model. There was no apparent difference in crawler activity between upper and lower branches of crapemyrtle trees across an entire season. This study provides the first set of population dynamics data for crapemyrtle bark scale in the U.S. and will help with future bark scale management decisions. Index words:, Crapemyrtle bark scale, invasive insect, population dynamics, Lagerstroemia spp Species used in this study: Crapemyrtle bark scale (Acanthococcus lagerstroemiae Kuwana); Crapemyrtle (Lagerstroemia spp.)

Analytical Discrete-Time Models of Insect Population Dynamics

Insect population dynamics has been extensively studied using two different approaches: continuous-time and discrete-time models. The continuous-time framework is generally used to model populations with overlapping generations and all year-round reproduction. In contrast, discrete-time models are more suited for populations with non-overlapping generations that reproduce in a discrete pulse determined by season. We revisit simple models of host-parasitoid interactions and describe tools for elucidating their dynamical behaviors. One advantage of simple models is that they are often analytically tractable providing key insights into regulatory mechanisms and parameter regions that lead to stable, unstable or oscillatory population dynamics. While reviewing classical models introduced decades ago, we also highlight new modeling frameworks and results from recent literature.

Moving on from the insect apocalypse narrative: engaging with evidence-based insect conservation

Recent studies showing temporal changes in local and regional insect populations received exaggerated global media coverage. Confusing and inaccurate science communication on this important issue could have counter-productive effects on public support for insect conservation. The ‘insect apocalypse’ narrative is fuelled by a limited number of studies that are restricted geographically (predominantly UK, Europe, USA) and taxonomically (predominantly bees, macrolepidoptera, and ground beetles). Biases in sampling and analytical methods (e.g. categorical vs. continuous time series, different diversity metrics) limit the relevance of these studies as evidence of generalised global insect decline. Rather, the value of this research lies in highlighting important areas for priority investment. We summarise research, communication and policy priorities for evidence-based insect conservation, including key areas of knowledge to increase understanding of insect population dynamics. Importantly, we advocate for a balanced perspective in science communication to better serve both public and scientific interests.

Influence of abiotic factors on the resistance of plants to insects

Plant resistance is considered as an important pillar of Integrated Pest Management (IPM), being a highly targeted method since is a less harmful method to the environment, if compared to other tactics such as chemical control. Abiotic factors are those related to the environment and have a direct influence on the dynamics of interaction between insects and plants. The abiotic factors such as altitude, temperature, humidity, luminosity, wind and soil fertility, among others, do not act alone, but in a complex net that leads insect population dynamics in agroecosystems. How the variations of these factors can be studied in the same context? First, it is important to consider how each abiotic factors act separately and then in a coexistence influence over the populations dynamics of insects and plants. In this study, the literature about the influence of abiotic factors on insect herbivory has been reviewed, focusing mainly on the mechanisms in which the plants use in the defense against insects.Influência de fatores abióticos na resistência de plantas a insetos Resumo. A resistência de plantas é considerada um importante pilar no contexto do Manejo Integrado de Pragas (MIP), sendo um método bastante visado por ser menos nocivo ao meio ambiente, quando comparado a outras táticas como o controle químico. Os fatores abióticos são aqueles relacionados ao ambiente e têm influência direta na dinâmica de interação entre insetos e plantas. Os fatores abióticos como altitude, temperatura, umidade, luminosidade, ventos e fertilidade do solo, por exemplo, não atuam sozinhos, mais sim em um complexo de fatores coexistentes que regem as dinâmicas populacionais nos diversos agroecosistemas. Como as variações destes fatores podem ser estudadas em um mesmo contexto? Primeiramente, é importante conhecer como cada uma atua individualmente para então contextualizar em uma situação de coexistência sobre as dinâmicas populacionais de insetos e plantas. Neste artigo, a literatura sobre a influência de fatores abióticos na herbivoria de insetos foi revisada, focando principalmente nos mecanismos em que as plantas utilizam na defesa contra insetos.