Insect Diapause

Our highly seasonal world restricts insect activity to brief portions of the year. This feature necessitates a sophisticated interpretation of seasonal changes and enactment of mechanisms for bringing development to a halt and then reinitiating it when the inimical season is past. The dormant state of diapause serves to bridge the unfavourable seasons, and its timing provides a powerful mechanism for synchronizing insect development. This book explores how seasonal signals are monitored and used by insects to enact specific molecular pathways that generate the diapause phenotype. The broad perspective offered here scales from the ecological to the molecular and thus provides a comprehensive view of this exciting and vibrant research field, offering insights on topics ranging from pest management, evolution, speciation, climate change and disease transmission, to human health, as well as analogies with other forms of invertebrate dormancy and mammalian hibernation.

Flower-visiting insects to Coffea arabica flower at different temperatures and the production of the fruit of arabica coffee

Temperature change may affect insect activity, including flower-visiting insects. Flower-visiting insects, particularly pollinators, have an impact on the fruits produced. This research aimed to study the relationships of flower-visiting insects at different temperatures and coffee production. The gauze experiment was carried out on the coffee plantation that consists of two sites, shaded and unshaded. The study involved 30 arabica inflorescences. The number of flower-visiting insects was recorded and captured. The results showed that the diversity of flower-visiting insects was related to the temperature differences. The flower-visiting insect on the unshaded site was more diverse than the shaded site. The formation of peaberries and the productivity of coffee fruit were also different. Peaberry production was lower (6.24 %) while the fruit mass was heavier (0.15±0.096 g/cherry) in unshaded than shaded sites. However, at the unshaded, the percentage of coffee beans defect was 0.56 % greater than the shaded one. According to these findings, more flower-visiting insects lead to the lower peaberry formation, the heavier fruit mass but potentially causing higher defective coffee beans. The increase in temperature due to climate change can be detrimental because these phenomena will increase the number of coffee fruit defects and insect pests.

Diverse Response Diversity in Pollinators: Implications to the Resilience of Pollination Services in Buckwheat

Response diversity to environmental change among species is important for the maintenance of ecosystem services, but response diversity to changes in multiple environmental parameters is largely unexplored. Here, we examined how insect visitations to buckwheat flowers differ among species groups in response to changes in multiple weather variables and landscape structures.We found differences in responses to changes in weather conditions among insect taxonomic groups visiting buckwheat flowers. Specifically, beetles, butterflies, and wasps were more active in sunny and/or high-temperature conditions, whereas ants and flies showed the opposite pattern. Furthermore, responses to weather conditions differed between large and small insects, which agreed with the expectation that optimal temperature for insect activity has a positive association with body size. Response diversity per se was also diverse. For instance, large insects were responsive to temperatures more than small insects while smaller insects were responsive to sunshine duration more than large insects. Responses to spatial variables also differed; large insects were more abundant in fields with surrounding forests and mosaic habitats, whereas small insects were not. We suggest that the “diversity” in “response diversity,” which is a higher-order response diversity, should be a focus of future studies of the biodiversity–ecosystem service relationships.

Estimating the differences in critical thermal maximum and metabolic rate of Helicoverpa punctigera (Wallengren) (Lepidoptera: Noctuidae) across life stages

Temperature is a crucial driver of insect activity and physiological processes throughout their life-history, and heat stress may impact life stages (larvae, pupae and adult) in different ways. Using thermolimit respirometry, we assessed the critical thermal maxima (CTmax-temperature at which an organism loses neuromuscular control), CO2 emission rate (V́CO2) and Q10 (a measure of V́CO2 temperature sensitivity) of three different life stages of Helicoverpa punctigera (Wallengren) by increasing their temperature exposure from 25 °C to 55 °C at a rate of 0.25 °C min−1. We found that the CTmax of larvae (49.1 °C ± 0.3 °C) was higher than pupae (47.4 °C ± 0.2 °C) and adults (46.9 °C ± 0.2 °C). The mean mass-specific CO2 emission rate (ml V́CO2 h−1) of larvae (0.26 ± 0.03 ml V́CO2 h−1) was also higher than adults (0.24 ± 0.04 ml V́CO2 h−1) and pupae (0.06 ± 0.02 ml V́CO2 h−1). The Q10: 25–35 °C for adults (2.01 ± 0.22) was significantly higher compared to larvae (1.40 ± 0.06) and Q10: 35–45 °C for adults (3.42 ± 0.24) was significantly higher compared to larvae (1.95 ± 0.08) and pupae (1.42 ± 0.98) respectively. We have established the upper thermal tolerance of H. punctigera, which will lead to a better understanding of the thermal physiology of this species both in its native range, and as a pest species in agricultural systems.

Coffee crop weeds: refuge and food source for pests’ natural enemies

Weeds in coffee crops have diverse ecosystem services, such as sheltering and feeding natural enemies of pest insects. This study aimed to identify the potential of coffee weeds as food and refuge for natural enemies in shaded and sun coffee crops. Weeds were sampled in a 100 m transect installed in each type of coffee crop. Malaise traps and sweep-nets were both used to capture insects every 15 days for five months. After identifying the dominant weeds, observations and a direct recollection of insects were carried out at three different hours during three days. Faunistic analyses were performed, as well as the Bray and Curtis similarity analysis and the Student's t test. Emilia sonchifolia, Acmella oppositifolia, Bidens pilosa were predominant in the free exposure sun plantation coffee crops and Commelina diffusa, Salvia palifolia, Stachytarpheta cayennensis in under shade coffee crops. High insect activity was found between 11:30 am-12:00 pm. In these weeds, we found about 15 families, the most important were Formicidae, Braconidae, and Coccinellidae. We concluded that the shaded coffee crops exhibited a natural enemy community similar to that of the sun. Through this exploratory study, we verified that weeds harbor a diversity of natural enemies important to the coffee agroecosystems.

Inexpensive monitoring of flying insect activity and abundance using wildlife cameras

The ability to measure flying insect activity and abundance is important for ecologists, conservationists and agronomists alike. However, existing methods are laborious and produce data with low temporal resolution (e.g. trapping and direct observation), or are expensive, technically complex, and require vehicle access to field sites (e.g. radar and lidar entomology).We propose a method called “camfi” for long-term non-invasive monitoring of the activity and abundance of low-flying insects using images obtained from inexpensive wildlife cameras, which retail for under USD$100 and are simple to operate. We show that in certain circumstances, this method facilitates measurement of wingbeat frequency, a diagnostic parameter for species identification. To increase usefulness of our method for very large monitoring programs, we have developed and implemented a tool for automatic detection and annotation of flying insect targets based on the popular Mask R-CNN framework. This tool can be trained to detect and annotate insects in a few hours, taking advantage of transfer learning.We demonstrate the utility of the method by measuring activity levels and wingbeat frequencies in Australian Bogong moths Agrotis infusa in the Snowy Mountains of New South Wales, and find that these moths have a mean wingbeat frequency of 48.6 Hz (SE = 1.4), undertake dusk flights in large numbers, and that the intensity of their dusk flights is modulated by daily weather factors. Validation of our tool for automatic image annotation gives baseline performance metrics for comparisons with future annotation models. The tool performs well on our test set, and produces annotations which can be easily modified by hand if required. Training completed in less than 2 h on a single machine, and inference took on average 1.15 s per image on a laptop.Our method will prove invaluable for ongoing efforts to understand the behaviour and ecology of the iconic Bogong moth, and can easily be adapted to other flying insects. The method is particularly suited to studies on low-flying insects in remote areas, and is suitable for very large-scale monitoring programs, or programs with relatively low budgets.

The seasonal dynamics of a High Arctic plant - visitor network: temporal observations and responses to delayed snow melt

Plant - visitor food webs provide important insights into species interactions, and more information about their seasonal dynamics is vital to understanding the resilience of species to external pressures. Studies of Arctic networks can also improve our understanding of species responses to the pressures of climate change. This study provides the first description of a plant – insect visitor network in Svalbard, a High Arctic archipelago already experiencing the consequences of climate change. A subset of the network was collected from experimental plots where the snow melt date was delayed with snow fences. The deep snow plots delayed flowering and we expected this to disrupt plant-visitor interactions compared to ambient snow conditions. However, the composition of flowers and insect visitors were similar between regimes, and the network tracked patterns of overall flowering phenology. Nevertheless, the deep snow significantly reduced the average overlap between flower availability and insect activity, reducing the probability of an interaction. We suggest that at a landscape scale, Arctic pollinators will benefit from patchy changes to snow melt that maintain heterogeneity in the timing of flowering but changes that increase homogeneity in snowmelt across the landscape may negatively impact some species.

3. Flies Larva On White Rat Carcass (Rattus norvegicus Berkenhout, 1769) With Various Treatment Outdoor

Insect activity including its life cycle can determine the estimated time of death or Post Mortem Interval (PMI). One type of insect that plays an important role in determining the estimated time of death is flies. This study aims to determine the types of flies that come to the carcass and to determine the types of flies that dominate and less dominate from each treatment onwhite rat (carcassesR. norvegicusmale) outdoors. This study consisted of 3 treatments with 3 repetitions each. The treatments included A (neck bone dislocation), B (burned), and C (poisoned). Carcass observations were carried out for 10 days and larvae collection was carried out every 2 days starting from the third day of observation. The parameters observed included the number and morphological characteristics of instar 3 fly larvae. The types of fly larvae found in all treatments were Lucilia illustris (5.42%), Sarcophaga sp (12.80%), Sarcophaga argyrostoma (30.62%), and Sarcophaga variegata (51.16%). The dominant fly larvae of the three treatments was S. variegata and the less dominant fly larvae was L. illustris.

A DNA-based method for distinction of fly artifacts from human bloodstains

Fly artifacts resulting from insect activity could act as confounding factors on a crime scene and interfere with bloodstain pattern analysis interpretation. Several techniques have been proposed to distinguish fly artifacts from human bloodstains based on morphological approach and immunological assay, but a DNA-based method has not been developed so far. Even if in forensic genetic investigations the detection of human DNA is generally the primary goal, fly artifacts can provide useful information on the dynamics of crime events. The present study provides a molecular method to detect fly DNA from artifacts deposited by Calliphora vomitoria after feeding on human blood through the analysis of the mitochondrial cytochrome oxidase gene subunit I (COI). Fly artifacts originated from digestive process and of different morphology spanning from red and brownish/light brown, circular and elliptical stains to artifacts with sperm-like tail or a tear-shaped body were collected. The COI amplification was successfully obtained in 94% of fly artifact samples. The method showed high sensitivity and reproducibility, and no human DNA contamination was observed, offering specificity for use in confirmatory test. This molecular approach permits the distinction of fly artifacts from genuine bloodstains and the identification of fly’s species through the COI region sequencing by protocols usually applied in forensic genetic laboratories.