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Proceedings of the National Academy of... Dec 2021Choosing among spatially distributed options is a central challenge for animals, from deciding among alternative potential food sources or refuges to choosing with whom...
Choosing among spatially distributed options is a central challenge for animals, from deciding among alternative potential food sources or refuges to choosing with whom to associate. Using an integrated theoretical and experimental approach (employing immersive virtual reality), we consider the interplay between movement and vectorial integration during decision-making regarding two, or more, options in space. In computational models of this process, we reveal the occurrence of spontaneous and abrupt "critical" transitions (associated with specific geometrical relationships) whereby organisms spontaneously switch from averaging vectorial information among, to suddenly excluding one among, the remaining options. This bifurcation process repeats until only one option-the one ultimately selected-remains. Thus, we predict that the brain repeatedly breaks multichoice decisions into a series of binary decisions in space-time. Experiments with fruit flies, desert locusts, and larval zebrafish reveal that they exhibit these same bifurcations, demonstrating that across taxa and ecological contexts, there exist fundamental geometric principles that are essential to explain how, and why, animals move the way they do.
Topics: Animals; Behavior, Animal; Decision Making; Drosophila melanogaster; Grasshoppers; Larva; Models, Theoretical; Motor Activity; Social Behavior; Zebrafish
PubMed: 34880130
DOI: 10.1073/pnas.2102157118 -
Proceedings of the National Academy of... Jan 2020Gravity is one of the most ubiquitous environmental effects on living systems: Cellular and organismal responses to gravity are of central importance to understanding...
Gravity is one of the most ubiquitous environmental effects on living systems: Cellular and organismal responses to gravity are of central importance to understanding the physiological function of organisms, especially eukaryotes. Gravity has been demonstrated to have strong effects on the closed cardiovascular systems of terrestrial vertebrates, with rapidly responding neural reflexes ensuring proper blood flow despite changes in posture. Invertebrates possess open circulatory systems, which could provide fewer mechanisms to restrict gravity effects on blood flow, suggesting that these species also experience effects of gravity on blood pressure and distribution. However, whether gravity affects the open circulatory systems of invertebrates is unknown, partly due to technical measurement issues associated with small body size. Here we used X-ray imaging, radio-tracing of hemolymph, and micropressure measurements in the American grasshopper, , to assess responses to body orientation. Our results show that during changes in body orientation, gravity causes large changes in blood and air distribution, and that body position affects ventilation rate. Remarkably, we also found that insects show similar heart rate responses to body position as vertebrates, and contrasting with the classic understanding of open circulatory systems, have flexible valving systems between thorax and abdomen that can separate pressures. Gravitational effects on invertebrate cardiovascular and respiratory systems are likely to be widely distributed among invertebrates and to have broad influence on morphological and physiological evolution.
Topics: Adaptation, Physiological; Animals; Blood Pressure; Body Size; Cardiovascular Physiological Phenomena; Grasshoppers; Gravitation; Respiratory Physiological Phenomena
PubMed: 31932424
DOI: 10.1073/pnas.1915424117 -
Viruses Dec 2022Grasshoppers can swarm in the millions and destroy crops over wide areas, posing a major economic threat to agriculture. A wide range of insect-related viruses has...
Grasshoppers can swarm in the millions and destroy crops over wide areas, posing a major economic threat to agriculture. A wide range of insect-related viruses has recently been reported in the metagenomics of grasshoppers. Here, we identified and isolated a novel reovirus from grasshoppers, named Acrididae reovirus (ARV). The complete genome of ARV was composed of nine dsRNA segments. Phylogenetic analysis revealed that ARV formed a monophyletic lineage with unclassified insect-associated reoviruses and was sufficiently distinct from known genera of . ARV could replicate in its host and result in host death. Lower-dose ARV infection affected ovary development and resulted in a significant reduction in fecundity. The identification and characterization of a novel pathogenic reovirus could potentially promote the development of new biological control agents.
Topics: Animals; Grasshoppers; Phylogeny; Reoviridae; Orthoreovirus; Reoviridae Infections
PubMed: 36560814
DOI: 10.3390/v14122810 -
Journal of Comparative Physiology. A,... May 2021One hundred years ago in 1921, Sir Boris Uvarov recognized that two locust species are one species but appearing in two different phases, a solitarious and a gregarious... (Review)
Review
One hundred years ago in 1921, Sir Boris Uvarov recognized that two locust species are one species but appearing in two different phases, a solitarious and a gregarious phase. As locust swarms are still a big problem affecting millions of people, basic research has tried to understand the causes for the transition between phases. This phenomenon of phase polymorphism, now called polyphenism, is a very complex multifactorial process and this short review will draw attention to this important aspect of insect research.
Topics: Animals; Behavior, Animal; Biogenic Amines; Biological Evolution; Biomedical Research; Female; Genotype; Grasshoppers; History, 20th Century; History, 21st Century; Male; Neurophysiology; Phenotype; Pheromones; Population Density; Sensory Thresholds; Social Behavior; Species Specificity
PubMed: 33871680
DOI: 10.1007/s00359-021-01485-3 -
Science Progress Oct 2021Grasshoppers and locusts are widely distributed worldwide, causing significant losses in agriculture. The origin and functions of their haemocytes are not entirely...
INTRODUCTION
Grasshoppers and locusts are widely distributed worldwide, causing significant losses in agriculture. The origin and functions of their haemocytes are not entirely understood.
OBJECTIVES
Insect haemocytes arbitrate cellular defence and participate in humoral defences. Due to their importance, the haemocytes of 35 species of grasshoppers and locusts from China were morphologically examined in this study. We aim to highlight a simple method for the morphological examination of insect haemocytes.
METHODS
The haemocytes were observed, counted and compared under a light microscope after Wright-Giemsa staining.
RESULTS
High complexity in form and shape were observed in the haemocytes. These include prohaemocytes, plasmatocytes, granulocytes, vermicytes, podocytes and megakaryocytes. No clear relationship was seen between the haemocyte type and their phylogenetic relationship among the three families examined. The high abundance of plasmatocytes and granulocytes suggests their importance in the immunity of grasshoppers and locusts. The minor haemocyte populations including prohaemocytes, vermicytes and podocytes may not be always present in individuals.
CONCLUSION
All examined species shared similarities in their haemocyte types. Wright-Giemsa staining is a simple and efficient method for evaluating haemocytes.
Topics: Animals; Granulocytes; Grasshoppers; Hemocytes; Humans; Phylogeny; Staining and Labeling
PubMed: 34751063
DOI: 10.1177/00368504211053551 -
International Journal of Molecular... Jan 2022Tissue homeostasis is critical for maintaining organ shape, size, and function. The condition is regulated by the balance between the generation of new cells and the...
Tissue homeostasis is critical for maintaining organ shape, size, and function. The condition is regulated by the balance between the generation of new cells and the loss of senescent cells, and it involves many factors and mechanisms. The midgut, an important part of the intestinal tract, is responsible for digestion and nutrient absorption in insects. LmDDX47, the ortholog of DEAD-box helicase 47 from , is indispensable for sustaining a normal midgut in the nymphs. However, the underlying cellular and molecular mechanisms remain to be elucidated. In this study, knockdown resulted in atrophy of the midgut and gastric cecum in both nymph and adult locusts. After knockdown, the number of regenerative and columnar cells in the midgut was significantly reduced, and cell death was induced in columnar tissue. LmDDX47 was localized to the nucleolus; this was consistent with the reduction in 18S rRNA synthesis in the knockdown group. In addition, the acetylation and crotonylation levels of midgut proteins were significantly increased. Therefore, could be a key regulator of midgut homeostasis, regulating 18S rRNA synthesis as well as protein acetylation and crotonylation in the migratory locust.
Topics: Animals; DEAD-box RNA Helicases; Digestive System; Digestive System Physiological Phenomena; Female; Gene Expression Regulation; Homeostasis; Locusta migratoria; Male; RNA, Ribosomal, 18S
PubMed: 35054771
DOI: 10.3390/ijms23020586 -
Journal of Evolutionary Biology Feb 2022Variation in development time can affect life-history traits that contribute to fitness. In Gryllus vocalis, a non-diapausing cricket with variable development time, we...
Variation in development time can affect life-history traits that contribute to fitness. In Gryllus vocalis, a non-diapausing cricket with variable development time, we used a path analysis approach to determine the causative relationships between parental age, offspring development time and offspring life-history traits. Our best-supported path model included both the effects of parental age and offspring development time on offspring morphological traits. This result suggests that offspring traits are influenced by both variation in acquisition of resources and trade-offs between traits. We found that crickets with longer development times became larger adults with better phenoloxidase-based immunity. This is consistent with the hypothesis that crickets must make a trade-off between developing quickly to avoid predation before reproduction and attaining better immunity and a larger adult body size that provides advantages in male-male competition, mate choice and female fecundity. Slower-developing crickets were also more likely to be short-winged (unable to disperse by flight). Parental age has opposing direct and indirect effects on the body size of daughters, but when both the direct and indirect effects of parental age are taken into account, younger parents had smaller sons and daughters. This pattern may be attributable to a parental trade-off between the number and size of eggs produced with younger parents producing more eggs with fewer resources per egg. The relationships between variables in the life-history traits of sons and daughters were similar, suggesting that parental age and development time had similar causative effects on male and female life-history traits.
Topics: Animals; Body Size; Female; Gryllidae; Life History Traits; Male; Phenotype; Reproduction
PubMed: 34882888
DOI: 10.1111/jeb.13971 -
PloS One 2024Haiku are short poems, each composed of about 10 words, that typically describe moments in nature. People have written haiku since at least the 17th century, and the...
Haiku are short poems, each composed of about 10 words, that typically describe moments in nature. People have written haiku since at least the 17th century, and the medium continues to be popular with poets, amateurs, educators, and students. Collectively, these poems represent an opportunity to understand which aspects of nature-e.g., which taxa and biological traits-resonate with humans and whether there are temporal trends in their representation or the emotions associated with these moments. We tested this potential using a mix of linguistic and biological methods, in analyses of nearly 4,000 haiku that reference arthropods. We documented the taxa and the life history traits represented in these poems and how they changed over time. We also analyzed the poems for emotion and tone. Our results reveal a mix of predictable trends and compelling surprises, each of which stand to potentially inform engagement strategies. At least 99 families of arthropods, in 28 orders, are represented in these haiku. The eight most commonly referenced taxa, from highest to lowest number of references, include: Lepidoptera, Hymenoptera, Diptera, Coleoptera, Araneae, Orthoptera, Hemiptera, and Odonata. Several common, conspicuous orders were never referenced, including Trichoptera, Plecoptera, and Megaloptera. The most commonly referenced traits relate to ecology (especially habitat, phenology, time of day), behavior (especially sound production), phenotype (especially color), and locomotion (especially flight). The least common traits in haiku relate to arthropod reproduction and physiology. Our analyses revealed few obvious temporal trends in the representations of taxa, biological traits, or emotion and tone. The broader implications of these results and possible future directions are discussed.
Topics: Animals; Humans; Arthropods; Insecta; Orthoptera; Coleoptera; Spiders
PubMed: 38568873
DOI: 10.1371/journal.pone.0298865 -
Journal of Insect Science (Online) Nov 2022Oedaleus asiaticus (Bey-Bienko) is an economically devastating locust species found in grassland and pastoral areas of the Inner Mongolia region of northern China. In...
Resistance to Beta-cypermethrin, Azadirachtin, and Matrine, and Biochemical Characterization of Field Populations of Oedaleus asiaticus (Bey-Bienko) in Inner Mongolia, Northern China.
Oedaleus asiaticus (Bey-Bienko) is an economically devastating locust species found in grassland and pastoral areas of the Inner Mongolia region of northern China. In this study, resistance to three frequently used insecticides (beta-cypermethrin, matrine, and azadirachtin) was investigated in six field populations of O. asiaticus using the leaf-dip bioassay method. The inhibitory effects of synergists and the activities of detoxification enzyme activities in the different populations were determined to explore potential biochemical resistance mechanisms. The results showed that the field populations SB (resistance ratio [RR] = 7.85), ZB (RR = 5.64), and DB (RR = 6.75) had developed low levels of resistance to beta-cypermethrin compared with a susceptible control strain. Both the SB (RR = 5.92) and XC (RR = 6.38) populations had also developed low levels of resistance against matrine, with the other populations remaining susceptible to both beta-cypermethrin and matrine. All field populations were susceptible to azadirachtin. Synergism analysis showed that triphenyl phosphate (TPP) and diethyl-maleate (DEM) increased the toxicity of beta-cypermethrin significantly in the SB population, while the synergistic effects of TPP, piperonyl butoxide (PBO), and DEM on the toxicity of matrine were higher in SB (SR 3.86, 4.18, and 3.07, respectively) than in SS (SR 2.24, 2.86, and 2.29, respectively), but no synergistic effects of TPP, PBO, and DEM on azadirachtin were found. Biochemical assays showed that the activities of carboxylesterases (CarEs) and glutathione-S-transferases (GSTs) were significantly raised in all field populations of O. asiaticus, with a significant positive correlation observed between beta-cypermethrin resistance and CarE activity. The activities of cytochrome P450 monooxygenases (P450) and multi-function oxidases (MFO) were elevated in all six field populations, and P450 activity displayed strong positive correlations with the three insecticides. Our findings suggest that resistance to beta-cypermethrin in O. asiaticus may be mainly attributed to elevated CarE and GST activities, while P450 plays an important role in metabolizing matrine and azadirachtin. Our study provides insights that will help improve insecticide resistance management strategies.
Topics: Animals; Insecticides; Pyrethrins; Insecticide Resistance; Grasshoppers; China; Matrines
PubMed: 36374481
DOI: 10.1093/jisesa/ieac063 -
Proceedings. Biological Sciences Jan 2023Collectively moving groups of animals rely on the decision-making of locally interacting individuals in order to maintain swarm cohesion. However, the complex and noisy...
Collectively moving groups of animals rely on the decision-making of locally interacting individuals in order to maintain swarm cohesion. However, the complex and noisy visual environment poses a major challenge to the extraction and processing of relevant information. We addressed this challenge by studying swarming-related decision-making in desert locust last-instar nymphs. Controlled visual stimuli, in the form of random dot kinematograms, were presented to tethered locust nymphs in a trackball set-up, while monitoring movement trajectory and walking parameters. In a complementary set of experiments, the neurophysiological basis of the observed behavioural responses was explored. Our results suggest that locusts use filtering and discrimination upon encountering multiple stimuli simultaneously. Specifically, we show that locusts are sensitive to differences in speed at the individual conspecific level, and to movement coherence at the group level, and may use these to filter out non-relevant stimuli. The locusts also discriminate and assign different weights to different stimuli, with an observed interactive effect of stimulus size, relative abundance and motion direction. Our findings provide insights into the cognitive abilities of locusts in the domain of decision-making and visual-based collective motion, and support locusts as a model for investigating sensory-motor integration and motion-related decision-making in the intricate swarm environment.
Topics: Animals; Visual Perception; Grasshoppers; Movement; Motion
PubMed: 36651041
DOI: 10.1098/rspb.2022.1862