Vertical Stratification of Insect Species Developing in Water-Filled Tree Holes

Forest ecosystems have a distinct vertical dimension, but the structuring of communities in this three-dimensional space is not well understood. Water-filled tree holes are natural microcosms structured in metacommunities. Here, we used these microcosms as model systems to analyze how insect communities and the occurrence and abundance of individual species are influenced by biotic and abiotic microhabitat characteristics, the vertical position of the tree hole, and stand-scale habitat availability. We found that both the characteristics of water-filled tree holes and their insect communities differ significantly between canopy and ground level. Individual insect species showed contrasting responses to the vertical position of the tree holes when important environmental factors at the stand and the tree-hole scale were considered. While some species, such as the mosquito Aedes geniculatus and the beetle Prionocyphon serricornis, decreased in abundance with increasing tree-hole height, the biting midge Dasyhelea sp., the non-biting midge Metriocnemus cavicola and the hoverfly Myiatropa florea increased in abundance. Our results suggest that vertical stratification in forests is most likely driven not only by variation in tree-hole microhabitat properties, i.e., niche separation, but also by individual species traits, such as adult dispersal propensity, food preferences and mating behavior of adult stages, and interspecific competition of larval stages. Therefore, communities of insect species developing in tree holes are likely structured by competition–colonization trade-offs predicted by metacommunity theory.

Inventory of insects in the El Ghrous's palm grove (Biskra; Algeria)

The diversity and species richness of insects were studied at the palm grove of El Ghrous. The insects were collected using two types of traps: Barber and Aerial. Forty-four insect species were inventoried. This inventory shows a predominance of Order Coleoptera with 6 families, 13 species and 241 individuals, followed by Hemiptera with 5 families, 7 species and 111 individuals, and Orthoptera with 2 families, 7 species and 54 individuals. J. Biodivers. Conserv. Bioresour. Manag. 2021, 7(1): 85-94

Effects of Mating on Gene Expression in Female Insects: Unifying the Field

There is intense interest in controlling insect reproductive output. In many insect species, reproductive output is profoundly influenced by mating, including the receipt of sperm and seminal fluid molecules, through physiological and behavior changes. To understand these changes, many researchers have investigated post-mating gene expression regulation. In this review, we synthesize information from studies both across and within different species about the impact of mating, or components of mating, on female gene expression patterns. We found that genes related to the roles of metabolism, immune-response, and chemosensation are regulated by mating across many different insect species. We highlight the few studies that have taken the important next step of examining the functional consequences of gene expression regulation which is crucial in order to understand the mechanisms underlying the mating-regulated control of female lifespan and reproduction and to make use of such knowledge to propagate or control insect populations. The potential of cross-study comparisons is diminished by different studies using different methods. Thus, we also include a consideration of how future studies could be designed to facilitate cross-study comparisons and a call for collaboration across researchers studying different insect species and different aspects of insect biology.

Mitochondria as a target and central hub of energy division during cold stress in insects

Temperature stress is one of the crucial factors determining geographical distribution of insect species. Most of them are active in moderate temperatures, however some are capable of surviving in extremely high as well as low temperatures, including freezing. The tolerance of cold stress is a result of various adaptation strategies, among others the mitochondria are an important player. They supply cells with the most prominent energy carrier—ATP, needed for their life processes, but also take part in many other processes like growth, aging, protection against stress injuries or cell death. Under cold stress, the mitochondria activity changes in various manner, partially to minimize the damages caused by the cold stress, partially because of the decline in mitochondrial homeostasis by chill injuries. In the response to low temperature, modifications in mitochondrial gene expression, mtDNA amount or phosphorylation efficiency can be observed. So far study also showed an increase or decrease in mitochondria number, their shape and mitochondrial membrane permeability. Some of the changes are a trigger for apoptosis induced via mitochondrial pathway, that protects the whole organism against chill injuries occurring on the cellular level. In many cases, the observed modifications are not unequivocal and depend strongly on many factors including cold acclimation, duration and severity of cold stress or environmental conditions. In the presented article, we summarize the current knowledge about insect response to cold stress focusing on the role of mitochondria in that process considering differences in results obtained in different experimental conditions, as well as depending on insect species. These differentiated observations clearly indicate that it is still much to explore. Graphical Abstract

Radar as a Key to Global Aeroecology

Open, systematic, and global approaches are needed to address the challenges of aeroconservation and pest management. Recent technical progress enables deeper investigation and understanding of aeroecology. Radar plays a central role in flying species monitoring in the global scope. The technology provides various ways of target detection and tracking, working for multiple ranges and different visibility. The existing technology allows deploying global monitoring of avian and insect species. This work discusses the essentials of the technology and the history of its application for bird and insect detection. The author describes the development of the topic according to the main groups of radar approaches: pulsed sets, vertical-looking solutions, harmonic systems, and efficient frequency modulated continuous wave radar. Advances in big data processing, robotics, computation, and communications enable practitioners to combine the discussed radar solutions aiming at global avian and insect biodiversity monitoring and negative human impact systematic estimation.

New data on some high-altitude protected insect species in northern Transbaikalia

The paper presents data on registration of two regionally protected insects in the north of Zabaykalsky krai. Observations were made in summer 2019-2021 in Kalarsky district of Zabaykalsky krai on the Ridges Udokan and Kodar. Parnassius eversmanni and Parnassius phoebus are characteristic and common species of high alpine meadows of the study area, especially at the Kodar Ridge between the Apsat and Sredny Sakukan Rivers. This area is not part of the Kodar National Park and requires attention for conservation of rich high altitude ecosystems that include the studied insect species.

Susceptibility of different life stages of Callosobruchus maculatus and Callosobruchus chinensis to ECO2FUME gas and its impact on cowpea seeds quality

ECO2FUME gas is an alternative to toxic phosphine fumigant and as a quarantine treatment for the control of a particularly recalcitrant pest, Callosobruchus maculatus and Callosobruchus chinensis. This gas was used to fumigate stored cowpea piles under gas-proof sheets to assess its performance against different developmental stages of Callosobruchus maculatus and Callosobruchus chinensis. The mortality was determined on four developmental stages of C. maculatus and C. chinensis, employing ECO2FUME at different concentrations 25, 30, 40, and 50 g/m3 for 3-days. All stages of both insect species in packed cowpea stacks were completely controlled at 3-days when applied with an ECO2FUME application rate of 50 g/m3. Cases of pupae of C. maculatus and C. chinensis exhibit the highest resistance than other stages, with 78.2 and 73.93% mortality respectively, at 40 g/m3 after 3-days post-exposure to ECO2FUME. Suppression of F1 generation was obtained after fumigation with the same concentration (50 g/m3). Quality (in terms of cowpea germination) and all chemical constituents of cowpea seeds were non significantly (P≤0.05) affected by the fumigation concentration of 50 g/m3.

Influence of the Foraging Activity of the Anthophilous Insects on Talinum triangulare (Waterleaf) fructification in Bafut (North West - Cameroon)

Talinum triangulare is an herbaceous succulent plant eaten as a vegetable throughout the tropics including many countries in West and Central Africa and are an essential ingredient in traditional dishes. Experiments were made on the plant to examine the influence of foraging behavior of flowering insect on pollination and yields of this plant species in 2018 and 2019 at Bafut. Observations were made on 1615 to 4055 flowers per treatment. The treatments included unlimited floral access by visitors and bagged flowers to deny all visits. The study focused on the foraging behavior of flowering insects and their pollination activity (fruiting rate). The results show that 14 insect species visited waterleaf flowers and Camponotus flavomarginatus was the most frequent (33.20%). Insects foraged throughout the day light period. Their activity was highest between 10 am and 12 pm. Insect species foraged the flowers for pollen and nectar. The fructification rate of unrestricted floral access was significantly high than that of protected flowers to deny all visits. The maintenance of insect nest close to T. triangulare field is recommended to improve it fruits production.

A Pilot Study of Natural Formulation Activity in the Protection of Stored Wheat and Barley Against the Stored-Product Insects

The stored-product insects are one of the major causes of losses in the stored cereals. Most of control measures still rely on a synthetic pesticide usage, but due to its negative side effects on the goods, human health, and the environment, there is an urgent need for an alternative control. A natural formulation based on the diatomaceous earth (DE) SilicoSec®, enhanced with the botanicals (essential oil lavender, corn oil, and bay leaves dust) and the silica gel was developed. The aim of the study was to test the activity of the developed formulation as a postharvest protectant of seed wheat and barley in the suppression Sitophilus oryzae (L.), Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst). As a reference comparative value, the DE SilicoSec® was applied. Subsequent to the six months of storage under the simulated warehouse conditions, the formulation has completely suppressed the initial population development of all three tested insect species, both in wheat and barley. In wheat, a complete suppression was detected at the dose of 500 ppm against T. castaneum and 600 ppm against both R. dominica and S. oryzae. In barley, a complete suppression was detected at the doses of 500 ppm, 400 ppm, and 600 ppm against R. dominica, T. castaneum and S. oryzae, respectively. Conclusively, the results of this study indicate that the developed natural formulation based on the DE, botanicals, and silica gel was highly effective against the three major stored‐product insect species, providing a long-term safe storage of wheat and barley seeds.