-
Ecology and Evolution May 2024The expansion of forest cover and intensification of agriculture represent the main threats to the bush cricket , currently listed as Vulnerable globally by the IUCN and...
The expansion of forest cover and intensification of agriculture represent the main threats to the bush cricket , currently listed as Vulnerable globally by the IUCN and included in Annex IV of the European Union Habitats Directive. Gathering information on its ecology and population size is challenging due to its low abundance and localized distribution. Additionally, the elusive and cryptic behavior of this species reduces the likelihood of its detection, potentially resulting in population underestimations. Thus, in this study, we aimed to (1) estimate population size in relation to environmental variables and prey availability and (2) predict abundance of in our study area for future monitoring in nearby territories. We found that the population of in our study area consists of 197 (±115) individuals with a detection probability of 21.01% (±11.09). Detection probability of further decreases on windy days. Moreover, we found that the investigated population of occupies suboptimal areas, as highlighted not only by the predicted abundances but also by the association between and other subfamilies of orthoptera that are ecologically very distant from our target species and mostly linked to mesophilic biotopes. Most of the individuals we observed are concentrated in small clearings completely within wooded matrices and therefore isolated from each other. Based on our results, it is possible that forest expansion toward open meadows represents the main threat to this population, transforming the clearings and xeric meadows (to which is linked) into small and fragmented patches that are suboptimal and insufficient to host viable populations.
PubMed: 38770125
DOI: 10.1002/ece3.11381 -
Biology Open Jun 2024Trait polymorphisms are widespread in nature, and explaining their stable co-existence is a central problem in ecology and evolution. Alternative reproductive tactics,...
Trait polymorphisms are widespread in nature, and explaining their stable co-existence is a central problem in ecology and evolution. Alternative reproductive tactics, in which individuals of one or more sex exhibit discrete, discontinuous traits in response to reproductive competition, represent a special case of trait polymorphism in which the traits are often complex, behavioural, and dynamic. Thus, studying how alternative reproductive tactics are maintained may provide general insights into how complex trait polymorphisms are maintained in populations. We construct a spatially explicit individual-based model inspired from extensively collected empirical data to address the mechanisms behind the co-existence of three behavioural alternative reproductive tactics in males of a tree cricket (Oecanthus henryi). Our results show that the co-existence of these tactics over ecological time scales is facilitated by the spatial structure of the landscape they inhabit, which serves to equalise the otherwise unequal mating benefits of the three tactics. We also show that this co-existence is unlikely if spatial aspects of the system are not considered. Our findings highlight the importance of spatial dynamics in understanding ecological and evolutionary processes and underscore the power of integrative approaches that combine models with empirical data.
Topics: Male; Gryllidae; Animals; Sexual Behavior, Animal; Reproduction; Biological Evolution; Phenotype
PubMed: 38738657
DOI: 10.1242/bio.060307 -
ZooKeys 2024The songs of seven grasshopper species of subfamily Gomphocerinae from Russia, Ukraine, Georgia, and Kazakhstan were studied. We analysed not only the sound, but also...
The songs of seven grasshopper species of subfamily Gomphocerinae from Russia, Ukraine, Georgia, and Kazakhstan were studied. We analysed not only the sound, but also the stridulatory movements of the hind legs to more entirely describe the songs. In , , and , the legs are moved in a relatively simple pattern; four other species, , , , and demonstrate more complex leg movements. In six of the seven species studied, the courtship songs contain more sound elements than the calling songs. The highest number of courtship sound elements was found in and The different parts of a remarkably long stridulatory file in are thought to participate in the production of different sound elements. The songs in are shown for the first time. This species produces sound not only by common stridulation but also by wing beats. A relationship of to some other species of the genus , which are able to crepitate, is discussed. We also analyse the frequency spectra of the songs. A maximum energy of the song power spectra in six species studied lies in ultrasound range (higher than 20 kHz). In only , the main peaks in the song power spectra lie lower than 20 kHz. The courtship behaviour in , , and was shown to include conspicuous visual display (movements of antennae, palps and the whole body).
PubMed: 38736699
DOI: 10.3897/zookeys.1200.118422 -
PloS One 2024Cricket Frass Fertilizer (CFF) was tested for its efficiency and potential as a fertilizer on the growth of green beans (Phaseolus vulgaris L.) in central Madagascar...
Cricket Frass Fertilizer (CFF) was tested for its efficiency and potential as a fertilizer on the growth of green beans (Phaseolus vulgaris L.) in central Madagascar from April 2020 to October 2020. We grew green beans experimentally for 93 days with seven different fertilizer treatments: NPK 200 kg/ha (0.47 g of N/plant), GUANOMAD (guano from bat) 300 kg/ha (0.26 g of N/ plant), CFF 100 kg/ha (0.12 g of N/plant), CFF 200 kg/ha (0.24 g of N/plant), CFF 300 kg/ha (0.38 g of N/plant), CFF 400 kg/ha (0.52 g of N/plant), and no fertilizer (0 g of N/plant). Three plant traits were measured: survival proportion, vegetative biomass, and pod biomass. The survival proportion of plants treated with the highest dose of CFF (400 kg/ha, 88.1%), NPK (79.8%), and GUANOMAD (81.2%) were similar, but plants treated with the former yielded significantly higher vegetative (35.5 g/plant) and pod biomass (11 g/plant). These results suggest that fertilizing green beans with CFF at a 400 kg/ha dose is sufficient for plant survival and growth, and improves pod production. In Madagascar where soil quality is poor, dependence on imported chemical fertilizers (NPK) and other organic fertilizer (GUANOMAD) can be reduced. Cricket Frass Fertilizer can be used as an alternative sustainable fertilizer for beans.
Topics: Fertilizers; Phaseolus; Biomass; Madagascar; Animals; Gryllidae
PubMed: 38722876
DOI: 10.1371/journal.pone.0303080 -
Philosophical Transactions of the Royal... Jun 2024Night-time light can have profound ecological effects, even when the source is natural moonlight. The impacts of light can, however, vary substantially by taxon, habitat...
Night-time light can have profound ecological effects, even when the source is natural moonlight. The impacts of light can, however, vary substantially by taxon, habitat and geographical region. We used a custom machine learning model built with the Python package to investigate the effects of moonlight on the calling activity of neotropical forest katydids over multiple years. We prioritised species with calls that were commonly detected in human annotated data, enabling us to evaluate model performance. We focused on eight species of katydids that the model identified with high precision (generally greater than 0.90) and moderate-to-high recall (minimum 0.35), ensuring that detections were generally correct and that many calls were detected. These results suggest that moonlight has modest effects on the amount of calling, with the magnitude and direction of effect varying by species: half of the species showed positive effects of light and half showed negative. These findings emphasize the importance of understanding natural history for anticipating how biological communities respond to moonlight. The methods applied in this project highlight the emerging opportunities for evaluating large quantities of data with machine learning models to address ecological questions over space and time. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.
Topics: Forests; Animals; Vocalization, Animal; Machine Learning; Light
PubMed: 38705184
DOI: 10.1098/rstb.2023.0110 -
Philosophical Transactions of the Royal... Jun 2024Insects are the most diverse animal taxon on Earth and play a key role in ecosystem functioning. However, they are often neglected by ecological surveys owing to the...
Insects are the most diverse animal taxon on Earth and play a key role in ecosystem functioning. However, they are often neglected by ecological surveys owing to the difficulties involved in monitoring this small and hyper-diverse taxon. With technological advances in biomonitoring and analytical methods, these shortcomings may finally be addressed. Here, we performed passive acoustic monitoring at 141 sites (eight habitats) to investigate insect acoustic activity in the Viruá National Park, Brazil. We first describe the frequency range occupied by three soniferous insect groups (cicadas, crickets and katydids) to calculate the acoustic evenness index (AEI). Then, we assess how AEI varies spatially and temporally among habitat types, and finally we investigate the relationship between vegetation structure variables and AEI for each insect category. Overall, crickets occupied lower and narrower frequency bands than cicadas and katydids. AEI values varied among insect categories and across space and time. The highest acoustic activity occurred before sunrise and the lowest acoustic activity was recorded in pastures. Canopy cover was positively associated with cricket acoustic activity but not with katydids. Our findings contribute to a better understanding of the role of time, habitat and vegetation structure in shaping insect activity within diverse Amazonian ecosystems. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'.
Topics: Animals; Brazil; Ecosystem; Vocalization, Animal; Acoustics; Gryllidae; Hemiptera; Orthoptera; Insecta
PubMed: 38705178
DOI: 10.1098/rstb.2023.0112 -
Die Naturwissenschaften May 2024Sedentary animals choose appropriate refuges against predators, while migratory ones may not necessarily do so. In ectotherms, refuge selection is critical during low...
Sedentary animals choose appropriate refuges against predators, while migratory ones may not necessarily do so. In ectotherms, refuge selection is critical during low temperatures, because they cannot actively evade predators. To understand how migratory ectotherms alter their defensive behaviors depending on refuge quality in cold temperatures, we evaluated migratory gregarious desert locust nymphs (Schistocerca gregaria) in the Sahara Desert, where daily thermal constraints occur. We recorded how roosting plant type (bush/shrub) and its height influenced two alternative defense behaviors (dropping/stationary) during cold mornings, in response to an approaching simulated ground predator. Most locusts in bushes dropped within the bush and hid irrespective of their height, whereas those roosting > 2 m height in shrubs remained stationary. These defenses are effective and match with refuge plant types because dynamic locomotion is not required. When nymphs roosted on shrubs < 1.5-m height, which was an unsafe position, nearly half showed both defensive behaviors, indicating that escaping decisions become ambiguous when the refuges are inappropriate. These results suggest that locusts display flexible defensive behaviors when finding appropriate refuges and selecting refuge before daily thermal limitations occur could be critical for migratory ectotherms, which is a risk associated with migration.
Topics: Animals; Nymph; Grasshoppers; Animal Migration; Cold Temperature; Desert Climate
PubMed: 38695961
DOI: 10.1007/s00114-024-01914-8 -
PloS One 2024Gryllus bimaculatus (Orthoptera: Gryllidae) is widely considered an excellent nutrient source for food and feed. Despite its economic importance, there is limited...
Impact of temperature on the bionomics and geographical range margins of the two-spotted field cricket Gryllus bimaculatus in the world: Implications for its mass farming.
Gryllus bimaculatus (Orthoptera: Gryllidae) is widely considered an excellent nutrient source for food and feed. Despite its economic importance, there is limited information on the impact of temperature on the bionomics of this cricket to guide its effective and sustainable mass production in its geographical range. The biological parameters of G. bimaculatus were investigated at eight different temperatures ranging from 20-40˚C. The Insect Life-Cycle Modelling (ILCYM) program was used to fit linear and non-linear functions to the data to describe the influence of temperature on life history parameters and its farmability under the current and projected climate for 2050. Our results revealed that G. bimaculatus was able to complete its lifecycle in the temperature range of 20°C to 37°C with a maximum finite rate of population increase (= 1.14) at 35°C. The developmental time of G. bimaculatus decreased with increasing temperature. The least developmental time and mortality were attained at 32°C. The highest wet length and mass of G. bimaculatus occurred at 32°C. The lowest temperature threshold for G. bimaculatus egg and nymph development was approximated using linear regression functions to be at 15.9°C and 16.2°C with a temperature constant of 108.7 and 555.6 degree days. The maximum fecundity (2301.98 eggs per female), net reproductive rate (988.42 daughters/ generation), and intrinsic rate of natural increase (0.134 days) were recorded at 32°C and the shortest doubling of 5.2 days was observed at 35°C. Based on our findings G. bimaculatus can be farmed in countries with temperatures ranging between 20 and 37°C around the globe. These findings will help the cricket farmers understand and project the cricket population dynamics around the world as influenced by temperature, and as such, will contribute to more efficient farming.
Topics: Animals; Gryllidae; Temperature; Female; Male; Life Cycle Stages
PubMed: 38687812
DOI: 10.1371/journal.pone.0300438 -
Journal of Economic Entomology Jun 2024Grass buffers are commonly planted along crop borders to filter nutrient and pesticide runoff. These buffers also provide food and shelter for beneficial and herbivorous...
Grass buffers are commonly planted along crop borders to filter nutrient and pesticide runoff. These buffers also provide food and shelter for beneficial and herbivorous arthropods and can serve as corridors for their movement into neighboring crops. Mowing is a common maintenance practice to control woody plants in these buffers. Field experiments were conducted to determine whether mowing influences the movement of arthropods into neighboring soybean plantings (Glycine max L) and impacts their abundance in corn (Zea mays var. indentata) the following spring. Results showed that mowing had varying effects on the abundance of herbivores, saprovores, parasitoids, and predators, particularly in the grass buffers. Aerially active arthropods in the plant canopy were more adversely affected by mowing than surface-dwelling arthropods. Mowing significantly reduced grasshopper (Orthoptera: Acrididae) density in the buffers, but did not trigger their movement into adjoining soybean fields. Parasitoids, predators, and thrips (Thysanoptera: Thripidae) were dissimilarly affected by mowing, and their responses were influenced by grass type. Altogether, these findings indicate that mowing did not cause notable movement of arthropods from grass buffers into adjoining crops and had minimal effects on the community of beneficial arthropods the following spring. Also, there were no differences in the level of insect feeding injury in crop fields next to mowed and unmowed buffers.
Topics: Animals; Glycine max; Zea mays; Arthropods; Insecta; Herbivory
PubMed: 38687132
DOI: 10.1093/jee/toae092 -
Pesticide Biochemistry and Physiology May 2024The Osiris gene family is believed to play important roles in insect biology. Previous studies mainly focused on the roles of Osiris in Drorophila, how Osiris operates...
The Osiris gene family is believed to play important roles in insect biology. Previous studies mainly focused on the roles of Osiris in Drorophila, how Osiris operates during the development of other species remains largely unknown. Here, we investigated the role of LmOsi17 in development of the hemimetabolous insect Locusta migratoria. LmOsi17 was highly expressed in the intestinal tract of nymphs. Knockdown of LmOsi17 by RNA interference (RNAi) in nymphs resulted in growth defects. The dsLmOsi17-injected nymphs did not increase in body weight or size and eventually died. Immunohistochemical analysis showed that LmOsi17 was localized to the epithelial cells of the foregut and the gastric caecum. Histological observation and hematoxylin-eosin staining indicate that the foregut and gastric caecum are deformed in dsLmOsi17 treated nymphs, suggesting that LmOsi17 is involved in morphogenesis of foregut and gastric caecum. In addition, we observed a significant reduction in the thickness of the new cuticle in dsLmOsi17-injected nymphs compared to control nymphs. Taken together, these results suggest that LmOsi17 contributes to morphogenesis of intestinal tract that affects growth and development of nymphs in locusts.
Topics: Animals; Locusta migratoria; Insect Proteins; Nymph; Morphogenesis; RNA Interference; Intestines
PubMed: 38685214
DOI: 10.1016/j.pestbp.2024.105860