ПАЛОЧНИКИ КАК ФАКТОР ПОЧВООБРАЗОВАНИЯ

Изучение существ – создателей важнейшего компонента жизни на планете – почвы, скорее всего, важная часть подготовки межпланетных космических команд. Работа представляет собой многоплановое исследование, где главным объектом выступает насекомое – Палочник аннамский. Автором проведены наблюдения за пищевой активностью и получены данные о количестве помета, то есть скорости формирования будущего гумуса. Проведено выращивание комнатного растения хлорофитум и оценено влияние смеси песка и гуано палочника на рост листьев и корней. Автору удалось провести серию химических анализов на количество нитратов в полученной «почве». Оценка концентрации нитратов в грунте проводилась как с помощью реагентов, так и с использованием прибора «Соэкс Эковизор F4». С их помощью получены данные о разных по времени формирования «почвах». The study of the creatures - creators of the most important component of life on the planet - the soil, first of all, is an important part of the preparation of interplanetary space teams. The work is a multifaceted study, where the main object is the insect – the Annam stick insect. The author carried out observations of food activity and obtained data on the amount of litter, that is, the rate of formation of future humus. A chlorophytum houseplant was grown and the effect of a mixture of sand and stick insect guano on the growth of leaves and roots was evaluated. The author managed to conduct a series of chemical analyses for the amount of nitrates in the resulting "soil". The assessment of the nitrate concentration in the soil was carried out both with the help of reagents and with the use of the device "Soex Ecovisor F4". With their help, data on "soils" of different formation times were obtained.

New taxonomic and ecological data for Paraprisopus apterus, the smallest stick insect from French Guiana (Phasmatodea, Pseudophasmatidae, Paraprisopodini)

The egg and the adult female of Paraprisopus apterus Conle, Hennemann, Bellanger, Lelong, Jourdan & Valero, 2020, from French Guiana, are described here for the first time. Ant-mimicking morphology and behaviour of post-hatch Paraprisopus nymphs are reported and discussed.

Dispersal of Phraortes illepidus (Phasmida: Phasmatidae) Eggs by Workers of the Queenless Ant, Pristomyrmex punctatus (Hymenoptera: Formicidae)

Eggs of some stick insects bear external appendages called capitula. Foraging worker ants attracted by capitula disperse eggs in a response similar to the responses of workers to elaiosome-bearing seeds of many plants. For this study, we conducted rearing experiments in the laboratory to elucidate the interspecific relation between the queenless ant, Pristomyrmex punctatus Smith, and the stick insect, Phraortes illepidus (Brunner von Wattenwyl) of which eggs bear capitula. Eggs of P. illepidus were proposed to P. punctatus in the laboratory. Capitula were removed from most of the eggs not only when ants were starved but also when ants were well-fed. In large rearing containers, eggs were transported by ants from their place of origin. Many eggs were transferred horizontally on the surface. Although some eggs were found in the artificial ant nests, it is likely that stick insects are not in active ant nests at the time of hatching in nature because of P. punctatus nest-moving habits. The percentage of eggs buried in the sand was small. Furthermore, most of the buried eggs were found at less than 3 cm depth. Results show that many P. illepidus hatchlings can reach host plants safely without being attacked by ant workers. These results suggest that P. punctatus can be a good partner of P. illepidus. Ants disperse eggs of slow-moving stink insects in exchange for some nutrition from capitula.

X chromosomes show a faster evolutionary rate and complete somatic dosage compensation across Timema stick insect species

Sex chromosomes have evolved repeatedly across the tree of life. As they are present in different copy numbers in males and females, they are expected to experience different selection pressures than the autosomes, with consequences including a faster rate of evolution, increased accumulation of sexually antagonistic alleles, and the evolution of dosage compensation. Whether these consequences are general or linked to idiosyncrasies of specific taxa is not clear as relatively few taxa have been studied thus far. Here we use whole-genome sequencing to identify and characterize the evolution of the X chromosome in five species of Timema stick insects with XX:X0 sex determination. The X chromosome had a similar size (approximately 11% of the genome) and gene content across all five species, suggesting that the X chromosome originated prior to the diversification of the genus. Genes on the X showed evidence of a faster evolutionary rate than genes on the autosomes, likely due to less effective purifying selection. Genes on the X also showed almost complete dosage compensation in somatic tissues (heads and legs), but dosage compensation was absent in the reproductive tracts. Contrary to prediction, sex-biased genes showed little enrichment on the X, suggesting that the advantage X-linkage provides to the accumulation of sexually antagonistic alleles is weak. Overall, we found the consequences of X-linkage on gene sequences and expression to be similar across Timema species, showing the characteristics of the X chromosome are surprisingly consistent over 30 million years of evolution.

Temporal Differences between Load and Movement Signal Integration in the Sensorimotor Network of an Insect Leg

Nervous systems face a torrent of sensory inputs, including proprioceptive feedback. Signal integration depends on spatially and temporally coinciding signals. It is unclear how relative time delays affect multimodal signal integration from spatially distant sense organs. We measured transmission times and latencies along all processing stages of sensorimotor pathways in the stick insect leg muscle control system using intra- and extracellular recordings. Transmission times of signals from load-sensing tibial and trochanterofemoral campaniform sensilla (tiCS, tr/fCS) to the premotor network were longer than from the movement-sensing femoral chordotonal organ (fCO). We characterized connectivity patterns from tiCS, tr/fCS, and fCO afferents to identified premotor nonspiking interneurons (NSIs) and motor neurons (MNs) by distinguishing short- and long-latency responses to sensory stimuli. Functional NSI connectivity depended on sensory context. The timeline of concurrent tiCS and fCO signals had an early phase of movement signal influences and delayed load influences. Temporal differences persisted into MN activity and muscle force development. We demonstrate a temporal difference in the processing of two distinct sensory modalities generated by the sensorimotor network and affecting motor output. The reported temporal differences in sensory processing and signal integration improve our understanding of sensory network computation and function in motor control.

Input of hair field afferents to a descending interneuron

In insects the tactile sense is important for near-range orientation and is involved in various behaviors. Nocturnal insects such as the stick insect Carausius morosus continuously explore their surroundings by actively moving their antennae when walking. Upon antennal contact with objects, stick insects show a targeted front-leg movement. As this reaction occurs within 40 ms, descending transfer of information from the brain to the thorax needs to be fast. So far, a number of descending interneurons have been described that may be involved in this reach-to-grasp behavior. One of these is the contralateral ON-type velocity-sensitive neuron (cONv). cONv was found to encode antennal joint-angle velocity during passive movement. Here, we characterize the transient response properties of cONv, including its dependence on joint angle range and direction. Since antennal hair field afferent terminals were shown to arborize close to cONv dendrites, we test whether antennal hair fields contribute to the joint-angle velocity encoding of cONv. To do so, we conducted bilateral extracellular recordings of both cONv interneurons per animal before and after hair field ablations. Our results show that cONv responses are highly transient, with velocity-dependent differences in delay and response magnitude. As yet, the steady state activity level was maintained until the stop of antennal movement, irrespective of movement velocity. Hair field ablation caused a moderate but significant reduction of movement-induced cONv firing rate by up to 40 %. We conclude that antennal proprioceptive hair fields contribute to the velocity-tuning of cONv, though further antennal mechanoreceptors must be involved, too.

Simplified Phasmatodea population evolution algorithm for optimization

This work proposes a population evolution algorithm to deal with optimization problems based on the evolution characteristics of the Phasmatodea (stick insect) population, called the Phasmatodea population evolution algorithm (PPE). The PPE imitates the characteristics of convergent evolution, path dependence, population growth and competition in the evolution of the stick insect population in nature. The stick insect population tends to be the nearest dominant population in the evolution process, and the favorable evolution trend is more likely to be inherited by the next generation. This work combines population growth and competition models to achieve the above process. The implemented PPE has been tested and analyzed on 30 benchmark functions, and it has better performance than similar algorithms. This work uses several engineering optimization problems to test the algorithm and obtains good results.

De novo transcriptome analysis for examination of the nutrition metabolic system related to the evolutionary process through which stick insects gain the ability of flight (Phasmatodea)

Objective Insects are the most evolutionarily successful groups of organisms, and this success is largely due to their flight ability. Interestingly, some stick insects have lost their flight ability despite having wings. To elucidate the shift from wingless to flying forms during insect evolution, we compared the nutritional metabolism system among flight-winged, flightless-winged, and flightless-wingless stick insect groups. Results Here, we report RNA sequencing of midgut transcriptome of Entoria okinawaensis, a prominent Japanese flightless-wingless stick insect, and the comparative analysis of its transcriptome in publicly available midgut transcriptomes obtained from seven stick insect species. A gene enrichment analysis for differentially expressed genes, including those obtained from winged vs wingless and flight vs flightless genes comparisons, revealed that carbohydrate metabolic process-related genes were highly expressed in the winged stick insect group. We also found that the expression of the mitochondrial enolase superfamily member 1 transcript was significantly higher in the winged stick insect group than in the wingless stick insect group. Our findings could indicate that carbohydrate metabolic processes are related to the evolutionary process through which stick insects gain the ability of flight.

Water Scorpions, Water Stick-Insects Ranatra spp. (Insecta: Hemiptera: Nepidae)

Commonly mistaken for other objects due to its appearance, hence the common name water stick-insect, this slender reddish-brown insect is commonly found in fresh or brackish water (a mix of salt and fresh water) (Anufriyeva et al. 2016). They are ambush predators and will spend most of its time in the water waiting for prey. They are limited to the length of their raptorial forearms in terms of catching prey. In the southeastern United States, these insects are commonly referred to as water scorpions. Also published on the Featured Creatures website at http://entnemdept.ufl.edu/creatures/AQUATIC/Ranatra.html