Insect Community Response Following Wildfire in an Eastern North American Pine Barrens

Ecosystem recovery following wildfire is heavily dependent upon fire severity and frequency, as well as factors such as regional topography and connectivity to unburned patches. Insects are an often-overlooked group of organisms impacted by fire and play crucial roles in many ecosystem services. Flying insects are particularly capable of avoiding fire, returning to burned patches following the initial disturbance, making them an important group to study when assessing wildfire impacts. Following a wildfire in July of 2018 at the Altona Flat Rock jack pine barrens in northeastern New York, insects were collected from an unburned reference site and a post-fire site using malaise traps. Samples were collected in the 2018, 2019, and 2020 field seasons. Insect groups were found to have three main responses to the disturbance event: increased abundance post-fire, unchanged abundance post-fire, or reduced abundance post-fire. Several dipteran families and some non-dipteran groups were present in greater abundance in the post-fire study site, such as Diptera Polleniidae, which increased in abundance immediately following the disturbance in 2018. Other fire-adapted taxa exhibited a more delayed positive response in 2019 and 2020. Diversity, particularly among Diptera, increased with time since the disturbance at the post-fire site. Many taxa declined in response to fire disturbance, including Lepidoptera and several Diptera families, most likely due to habitat, moisture, and organic matter requirements. Future studies could prove beneficial in understanding the recovery of this community and informing land management practices.

Degradative succession of the insects in small rodents in subtropical systems

We evaluated the insect succession in small rodent carcasses on the soil extracts (surface vs. buried) in two areas (riparian vs. agricultural) and two seasonal periods (spring vs. summer). Daily, the rodent carcasses were weighed and the insects present were collected in them for counting and family level identification. We also measured the air and soil temperature daily, in addition to the physical and chemical characteristics of the soil. The total of 11,059 individuals from 28 taxa was collected. The most abundant taxa were Calliphoridae (70%), Formicidae (20%), Muscidae (2%), and Sarcophagidae (2%). Insect richness was higher in spring in riparian vegetation areas; however, decomposition and insect abundance were greater in spring in agricultural areas by the high temperature measured. Vespidae, Sarcophagidae, Muscidae, and Calliphoridae decreased over time with abundance peaks respectively at 3, 7, 7, and 8 days in riparian vegetation areas. Calliphoridae decreased abundance over time with a peak at five days, but Armadillidiidae increased with peak at 6-9 days in agricultural areas. Decay and insect abundance was high in agricultural areas, mainly on the soil surface. Insect richness was high in riparian vegetation areas, especially on the soil surface. Only the superficial layers of soil presented taxon indicators and all decreased over time with abundance peaks of Calliphoridae, Sarcophagidae, and Muscidae at 5-8, 7, and 7 days, respectively. This abundance peak of insect families help to understand the degradative succession of the insect community in small rodents in subtropical systems of the neotropical region.

Evergreen Abundance Drives Ground Beetle Diversity And Density In Eastern Temperate Forests

Purpose: Soil insects mediate plant-soil interactions by fragmenting and decomposing litter that forms the base of soil food webs and through predator-prey interactions. Plant communities, in turn, shape soil insect communities via the quality, availability, and diversity of their litters. However, these drivers have rarely been examined in concert even though describing soil insect community patterns is critical for mitigating the effects of global environmental changes. Methods: Here, we evaluated the effects of tree diversity, density, and functional groups on ground beetle (Carabidae) diversity, density, and community composition in four eastern temperate forest sites in the National Ecological Observatory Network. Results Though we expected that higher tree diversity and density would, respectively, lead to higher diversity and density ground beetle communities, we found little evidence to support this hypothesis. Instead, evergreen tree abundance strongly shaped ground beetle diversity, density, and community composition. Specifically, evergreen plots as defined by National Land Cover Database hosted lower density ground beetle communities than deciduous plots. Similarly, ground beetle Shannon diversity and density decreased as the relative abundance of evergreen tree species increased. Conclusions: Although further study is needed to explicitly link litter quality with soil insect communities, the resource environments created by trees with varying leaf habits appear to be a dominant force driving ground beetle community diversity and density patterns.

Water Quality Assessment with Biotic Index Based on Abundance and Diversity of Aquatic Insects in a Hilly Stream, Bangladesh

Study of stream insect fauna provide valuable insights into aspects of the stream channel ecosystem. The present study was conducted to investigate the aquatic stream living insect community, abundance and diversity in a hilly stream, Balukhali chora of Chittagong University campus to determine the water quality. The insects were collected with bottom dredge net from the edge and benthic regions of the Riffle zone and the Pool zone of the stream from January 2018 to December 2018. Insects were sampled using standard entomological method and determined their tolerance value. A total of 2535 insects were recorded, belonging to six insect orders, 30 families and 45 genera. The abundance ratio was higher in all the months in the Pool zone excepting the months of April, May, June and October. The orders Ephemeroptera, Odonata and Diptera were abundant in the Pool zone, while Hemiptera, Coleoptera and Lepidoptera were abundant in the Riffle zone. On the basis of Biotic Index, the most dominating orders Odonata and Hemiptera indicated good water quality, though the dipteran genus Chironomus spp. indicated poor quality in some of the months. The stream insect community structure of the two zones indicated that the overall water quality of the stream water was very good. Both manmade and natural interruption occurred in the stream channel due to human settlement, agricultural runoff and natural disasters. The study was conducted to know the abundance and diversity of aquatic insect community which indicated the water quality of the stream.

Changes in nocturnal insect communities in forest-dominated landscape relevant to artificial light intensity

Background Artificial light at night has recently been identified as a major factor adversely affecting global insect diversity. Here, we compared the insect diversity in Gwangneung Forest Biosphere Reserve, specifically in the Korea National Arboretum (with no artificial light at night), with that of three nearby urban sites with a gradient of artificial light at night (five locations at each site). We analyzed the effects of the artificial night lighting index, mean annual temperature, and field light intensity (lux) at night on the insect community structure. Results The urban sites generally exhibited higher species richness and abundance as well as clear indicator species compared with the control site. The size distribution of the collected insects markedly differed between the control and the three urban sites. The abundance of herbivorous and omnivorous insects increased and decreased, respectively, with the increase in light intensity. Species richness of herbivorous and omnivorous insects was likely correlated with the field light intensity at night and artificial night lighting index, respectively. Conclusions This study demonstrates the association between nighttime environment and marked changes in insect community structure and revealed consequent transition of ecosystem services by changes in trophic group composition.

Effects of experimental multi-season drought on abundance, richness, and beta diversity patterns in perennially flowing stream insect communities

Freshwater systems are projected to experience increased hydrologic extremes under climate change. To determine how small streams may be impacted by shifts in flow regimes, we experimentally simulated flow loss over the span of three summers in nine 50 m naturally fed stream channels. The aquatic insect community of these streams was sampled before, during, and after experimental drought treatments as well as following one unforeseen flood event. Abundance, richness, and beta diversity were measured as indicators of biotic effects of altered flow regimes. Abundance declined in proportion to flow loss. In contrast, we observed a threshold response in richness where richness did not decrease except in channels where losses of surface flow occurred and disconnected pools remained. The flood reset this pattern, but communities continued their prior trajectories shortly thereafter. Beta diversity partitions suggested no strong compositional shifts, and that the effect of drought was largely experienced uniformly across taxa until flow cessation. Pools served as a refuge, maintaining stable abundance gradients and higher richness longer than riffles. Upon flow resumption, abundance and richness returned to pre-treatment levels within one year. Our results suggest that many taxa present were resistant to drought conditions until loss in surface flow occurred.

Postfire changes in chortobiont insects community at experimental plots in Southern Transbaikalia (Daursky Nature Reserve)

The purpose of the research is to study the features of the abundance of the chortobiont insect community in the burnt and unburned plots of the plain grasslands of the Torey depression in Southern Transbaikalia. In a number of cases, the diversity in the burned-out plots turned out to be significantly lower. This tendency remains throughout June and July, suggesting the importance of dry, dead grass, which serves as a shelter for invertebrates, providing better protection from predators and high temperatures. However, the species Trigonotylus longitarsus (Hemiptera, Miridae), on the contrary, showed an increase in abundance in the burnt plots.

The Ecology of Hyperparasitoids

Hyperparasitoids are some of the most diverse members of insect food webs. True hyperparasitoids parasitize the larvae of other parasitoids, reaching these larvae with their ovipositor through the herbivore that hosts the parasitoid larva. During pupation, primary parasitoids also may be attacked by pseudohyperparasitoids that lay their eggs on the parasitoid (pre)pupae. By attacking primary parasitoids, hyperparasitoids may affect herbivore population dynamics, and they have been identified as a major challenge in biological control. Over the past decades, research, especially on aphid- and caterpillar-associated hyperparasitoids, has revealed that hyperparasitoids challenge rules on nutrient use efficiency in trophic chains, account for herbivore outbreaks, or stabilize competitive interactions in lower trophic levels, and they may use cues derived from complex interaction networks to locate their hosts. This review focuses on the fascinating ecology of hyperparasitoids related to how they exploit and locate their often inconspicuous hosts and the insect community processes in which hyperparasitoids are prominent players. Expected final online publication date for the Annual Review of Entomology, Volume 67 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Assessment of Water Quality Parameters and Aquatic Insect Assemblages in Dalvoy Lake, Mysore District, Karnataka, India.

Water is an indispensable natural resource vital for the survival of all life forms. It contributes significantly to the country's economic prosperity and general well-being. As a result, understanding the status of water bodies is crucial to assure their long-term use. A study on water quality parameters and aquatic insect community was therefore carried on the surface waters of Dalvoy Lake which is spread over an area of 133.43 acres and having a length of 2.2 km. Monthly water samples were collected using one-litre labeled plastic containers from three locations between the hours of 8 a.m. and 10 a.m. Water quality analysis was conducted following standard methods and compared to drinking water specifications. The dissolved oxygen content, total hardness, conductivity, total dissolved solids, and turbidity exceeded the permissible limits. Aquatic insects were collected from the same locations and preserved in 4% formalin. A total of 15 species of aquatic insects belonging to four orders, Hemiptera, Coleoptera, Diptera, and Ephemeroptera, were identified in this study. The Hemiptera was shown to be the largest group comprising of 8 species; 4 species of Diptera; 2 species of Coleoptera and a lone species of Ephemeroptera. The computation of aquatic insect dominance status using Engelmann's Scale revealed Diplonychus rusticus, Anisops sp., Enithares sp., Chironomous sp. and Culex sp. as dominant. Biodiversity metrics like the Shannon Index (1.4-2.11) and the evenness index (0.50-0.66) reflect the agitation of the system. Based on the results of the water quality index (163.67) and aquatic insect assemblage, it is evident that the water in Dalvoy Lake is deteriorated and is unfit for domestic usage. The study also indicated the abundance of two genera Chironomous and Culex of the Diptera order which are the index of water pollution. Thus, the present study calls for urgent and strict vigilance and continuous monitoring of this perennial water body for conservation and sustainable management.