Insects

Black soldier fly larvae (BSFL) have quickly become one of the most farmed animals in the world. However, little is known about how to monitor stress and welfare in these animals. The difficulty of welfare assessment is compounded by the fact that BSFL live in their feed and prefer darkness. This behaviour makes it challenging to observe potential welfare indicators without inducing stress via disturbing the larvae or moving them into the light. However, acoustic devices may be able to pick up signatures of stress in the population even while they are out of sight, allowing for remote monitoring of animals in natural conditions (in the feed and/or in the dark). Acoustic monitoring of this type has been deployed for the detection of insects in stored grains, suggesting this method holds some promise for assessing insect behavioural signatures. In this study, we aimed to identify general, acoustic signatures of stress in BSFL by recording them during exposure to two stressors (light or shaking) or in a low-stress control condition. Our data suggest there are consistent differences in the acoustic recordings of the non-stressed and stressed conditions that may indicate the animals behaviours shift consistently in response to stress. Ultimately, the data suggest acoustic monitoring may hold promise for larval behaviour and/or welfare assessment and should be further explored in response to a variety of stressors across the larval life stage.

Life-history traits play an important role in insect population dynamics and ecological processes. The azuki bean beetle Callosobruchus chinensis is a common pest of stored legumes and is also widely used as a model species in ecological and evolutionary research. In this study, we tested whether machine learning models could be used to estimate several traits of C. chinensis, including elytral length, development time and adult lifespan. Experimental data were obtained from laboratory populations. The dataset included biological and environmental variables such as strain, treatment condition, developmental day, sex, temperature, and CO2. Six different machine learning models were tested, including linear regression, random forest, support vector machine (SVM), neural network, gradient boosting and AdaBoost. Model performance was evaluated using cross-validation. The coefficient of determination (R2) and root mean square error (RMSE) were used to measure prediction accuracy. Prediction accuracy differed among traits. Elytral length showed relatively higher predictability than the other traits, while development time was difficult to estimate in most models. Lifespan was easier to predict than the other traits, and the neural network produced one of the highest prediction accuracies among the tested models. Feature importance analysis also showed that factors such as sex and treatment condition contributed to variation in several traits. Machine learning models therefore helped reveal relationships among biological variables and life-history traits in C. chinensis. Combining ecological experiments with machine learning analysis may help improve our understanding of insect traits and may support future studies in insect ecology and pest management.

Honeybee breeding plans are relatively recent in most countries. In France, diverse small-scale breeding groups are emerging. Beekeepers are highly diverse in their motivations, farm productions and services, practices and management techniques. Yet, little is known about what beekeepers would consider as relevant breeding goals in the design of breeding plans. We therefore conducted an online survey answered by about 250 French beekeepers, mostly professionals, to assess their perceived importance of including 20 pre-defined traits in breeding goals and to identify how beekeeping profiles might influence these priorities. Respondents rated each trait as essential, useful, or useless, and indicated if they wished useful or essential traits to be genetically improved or merely maintained at their current level. Results indicated a strong preference for multi-trait selection, with a median of 13 traits considered useful or essential. Honey yield, disease resistance, swarming tendency, gentleness, and summer feed autonomy, emerged as the main traits of interest with about 90% of beekeepers finding them at least useful. About 40% or more only wished to maintain these traits at their current level rather than to directionally improve them. A major exception to this was disease resistance, that 75% wanted to improve. Bees genetic background influenced the most the importance attributed to breeding goal traits, while other beekeeping profile characteristics only had a marginal effect on breeding goal trait priorities. Some poorly studied traits, such as summer and winter feed autonomy, winter diapause, and longevity, were considered at least useful in a breeding goal by over 70% of beekeepers. Future research is needed to explore possible selection criteria for these traits and estimate the potential for their genetic improvement. ImplicationsOur survey shows that French beekeepers wish to improve or maintain through selective breeding usual colony production and behavioral traits, but also colony resilience, especially disease resistance and feed autonomy. However, trait priorities differ depending on the genetic background of the bees used. This knowledge is essential for designing breeding programs that truly match beekeeper needs and for identifying which traits deserve research attention. In France, beekeepers are increasingly starting breeding efforts to adapt their bees to current conditions, facing growing pressures from climate change, diseases, invasive species, and pesticides. Well-designed breeding programs can support sustainable beekeeping and essential pollination services.

Istocheta aldrichi (Diptera: Tachinidae), a specialist parasitoid of the invasive Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), was released to eastern North America in the 1920s as part of a classical biological control program. Further releases are being considered in different regions of North America and Europe where P. japonica is establishing. Successful releases of the biocontrol agent depend on identifying efficient techniques for collecting parasitized hosts from the field and rearing the parasitoid through diapause to obtain I. aldrichi adults. In this study, we evaluated how the collection date, the collection method (hand-picking vs. regular traps vs. modified traps) and rearing conditions (food provision and substrate type) of parasitized hosts influence I. aldrichi pupariation and emergence. The proportion of parasitized beetles yielding I. aldrichi puparia decreased considerably as the season progressed. Rearing conditions immediately after collection influenced both puparium yield and quality: withholding food from parasitized P. japonica slightly increased puparium yield but reduced puparium weight, while the effect of food provision on subsequent overwintering survival depended on rearing substrate. Finally, simple modifications to commercial traps (larger, ventilated, containers with added food source and substrate) collected more beetles than regular traps and promoted successful development of the parasitoid to the puparium stage. Our results are used to suggest basic guidelines for collecting and rearing I. aldrichi in experimental research and applied biological control of P. japonica.

Bird blowflies, Protocalliphora spp. (Diptera: Calliphoridae), are prevalent ectoparasites of altricial bird nestlings across the Holarctic region. Yet, their spatial and temporal dynamics of infestations, species composition, and interactions with parasitoids remain poorly understood. We present a 16-year (2004-2019) multisite study of bird blowfly infestations based on 2673 tree swallow, Tachycineta bicolor (Vieillot) (Passeriformes: Hirundinidae), nests collected across a 10 200-km{superscript 2} gradient of agricultural intensity in Quebec, Canada. Nest infestation prevalence and parasitic load varied markedly across space and time but showed synchronous recurrence at approximately 75% of sites, suggesting the influence of regional and local processes. Yearly rates of parasitoidism of bird blowfly puparia by Nasonia spp. wasps (Hymenoptera: Pteromalidae) were high but variable (48-90%), likely contributing to the temporal fluctuations in bird blowfly prevalence and load. Substantial interannual shifts in the relative abundance of Protocalliphora species (P. bennetti, P. metallica, and P. sialia) emphasised the importance of species-level identification in bird blowfly ecological studies. Large overlap in puparia size among species challenged the utility of traditional diagnostic traits for species identification. Finally, dormancy or mortality of Nasonia spp. occurred in 3-16% of Protocalliphora spp. puparia, depending on year. These findings highlight the importance of long-term, multitrophic, and spatially explicit monitoring to unravel the drivers of host-parasite-parasitoid dynamics.

This protocol generates gregarious and solitarious density-dependent phenotypes in multiple Schistocerca species under controlled environmental conditions. It describes cage setup, feeding, animal handling, and sterile dissection workflows to isolate nervous, chemosensory, gut, fat body, and female reproductive tissues from nymphs and adults. It emphasizes rapid tissue stabilization and RNase-control practices for downstream single-tissue DNA and RNA analyses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/705994v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@119ec2forg.highwire.dtl.DTLVardef@e115b7org.highwire.dtl.DTLVardef@158ad1dorg.highwire.dtl.DTLVardef@cd54d7_HPS_FORMAT_FIGEXP M_FIG C_FIG

Monomorium pharaonis is one of the many invasive ant species which can be found associated with the endosymbiont bacteria of the genus Wolbachia. The association of M. pharaonis ants with Wolbachia is still being studied but is already known for giving the colony a reproductive advantage. The present work aimed to use biodemography analysis to check the effect of Wolbachia in the colonies of M. pharaonis ants, regarding its reproductive potential and rate of fertility (fertility pace). We took advantage of Birch (1948) methods to assess the effect of the bacteria in the whole colony, using data of the Dryad project. We evaluated the mean length of the generation, its capacity to multiply and the intrinsic rate of increase (r) and if the presence of the bacteria favors the longevity of the colony. The results obtained in the present work confirmed our initial hypothesis that the presence of the endosymbiont bacteria Wolbachia increased the reproductive rates of M. pharaonis colonies. We also found that the employment of interdisciplinary approaches highly contributes to obtaining more accurate and quantifiable results. The application of this methodological approach, highly contributed to obtain more accurate and directly driven results. For example, colonies infected with Wolbachia showed higher intrinsic growth rate (r) and thus enlightening with a new methodological approach results already presented in previous research. This "new" methodological approach revealed itself as a new tool extendible to other ants colonies or even other species. The use of statistical and biodemographic formulas and the adaptation of classical demography concepts for the study of the growth and reproduction of ant colonies revealed to be very useful.

Insect research remains hindered by limited data availability and fragmented knowledge compared to other, better-documented taxonomic groups. Increasingly, both the macroecological and the insect research communities highlight the need to integrate large-scale ecological trait datasets for insects. We present AnthropInsect, the largest database on insect traits to date, which uniquely includes variables describing human-insect associations. AnthropInsect describes species through 35 variables grouped into five categories: (i) taxonomic descriptors; (ii) ecological descriptors (native bioregions and habitat); (iii) human-insect associations (edibility and invasive status); (iii) functional traits (behavior, morphology, life history and feeding); (iv) and macroecological descriptors of native-range geography and climate. AnthropInsect currently includes 5,870 species across six major orders: Coleoptera, Lepidoptera, Hemiptera, Hymenoptera, Orthoptera and Blattodea. Data extracted from peer-reviewed and grey literature and from existing databases were standardized and curated with expert knowledge to ensure accuracy. By providing traits data with information on insect- human interactions, this rigorously curated resource supports global research in entomology, ecology, conservation, and global change.

Insect camera traps are a rapidly developing technology, enabling automated monitoring of insects. However, little has been reported on improving the attractants used for daytime flying insects on such cameras. This study compares the attractiveness of novel, 3D printed, artificial flowers with traditional methods of attracting insects (e.g. pan traps and solid coloured paper squares). We hypothesised that artificial flowers would attract a higher abundance and diversity of insects compared to traditional attractants by more accurately mimicking flowers. Additionally, we examined colour preference and average landing duration on the attractants. Artificial flowers, dry pan traps and paper squares, painted in yellow, white, or blue ultraviolet fluorescent paint, were filmed simultaneously to observe wild insect behavioural responses (landings and approaches). The results indicate overall preference for artificial flowers over the two traditional attractants when considering all insect groups together, and overall colour preferences for blue and yellow. When analysing insect groups separately, hoverflies preferred landing on artificial flowers over the other attractants. Bumblebees preferred approaching artificial flowers, and small insects preferred landing and approaching artificial flowers over the other attractants. Other flies preferred landing on pan traps and paper over artificial flowers. Hoverflies, small insects, wasps, and solitary bees responded more to yellow than the other colours, while bumblebees responded more to blue. Comparisons of landing durations revealed that hoverflies spent longer on the artificial flowers than paper. Other flies spent longer on the pan traps and paper. These results show that artificial flowers could offer an efficient attractant for insect camera traps as they attracted a higher abundance of key pollinating insects (hoverflies and bumblebees), and do not have worse attraction rates for the other insect groups (excluding other flies).

Istocheta aldrichi (Diptera: Tachinidae) is a specialist parasitoid of the invasive Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae). Research and releases for biological control depend on field collecting parasitized hosts and rearing the parasitoid through diapause to obtain I. aldrichi adults. This study investigated how rearing practices before, during and after the seasonal overwintering period affected the proportion of I. aldrichi pupae that emerged as adults, the timing of parasitoid emergence, and their longevity. Increasing cold exposure duration during overwintering increased adult I. aldrichi emergence from puparia and reduced development time after transfer to warm conditions. Adult I. aldrichi emergence from overwintered puparia depended on interactions between overwintering environment (indoors vs. outdoors), spring thermal regime, and the timing of host collection in the previous season. Burying puparia in the soil in late summer/early fall resulted in higher subsequent adult I. aldrichi emergence. Manipulating spring temperatures in controlled environments allowed parasitoid emergence to be staggered over several weeks without reducing emergence success. Emergence under outdoor spring conditions was unreliable. Adult longevity was affected by temperature and diet: cooler conditions extended lifespan, honey-water increased longevity relative to pollen alone or honey-water and pollen together. These results provide a foundation to further improve I. aldrichi rearing techniques for use in experimental research and applied biological control of P. japonica.

BACKGROUNDInsect pests present a global threat to crops, with plant resistance representing a key breeding goal. The cabbage stem flea beetle (Psylliodes chrysocephala; CSFB) is the most damaging pest of oilseed rape (Brassica napus; OSR) within Europe; however, CSFB resistance is yet to be found within B. napus. To address this, we examine CSFB larval development over time, explore antibiosis across a diverse Brassica panel, and test whether larvae can develop within model Brassica relatives (Brassica rapa and Arabidopsis thaliana). RESULTSCSFB larvae completed development from four weeks post-infestation, undergoing a 20-fold size increase, with larval recovery after two weeks allowing semi-high throughput resistance phenotyping. Applying this method to 98 Brassica genotypes (97 B. napus and a single Sinapis alba), we found weak evidence for genotype effects on larval survival, however phenotype validation with resistant and susceptible B. napus genotypes showed no differences in larval survival or adult emergence. Larval antibiosis was consistently observed in S. alba. Finally, we showed that B. rapa and A. thaliana represent suitable hosts for CSFB, with larvae increasing 8-10x in size after two weeks. CONCLUSIONCSFB larval antibiosis appears absent within B. napus, possibly due to bottlenecks experienced during domestication. However, larval antibiosis is present within S. alba, and future work should study the basis of this resistance. Further, CSFB larval screening in Brassica relatives presents an opportunity to explore CSFB resistance genetics, informing breeding progress for insect resistance in B. napus.

It is commonplace in East Africa for 100% of cassava fields to be infected with Cassava mosaic disease (CMD) and/or Cassava brown streak disease (CBSD), resulting in annual losses of more than US$1.25 billion and reduced food and economic security for farming households. The vector of both diseases is the African cassava species of the whitefly Bemisia tabaci. Since the late 1990s, there has been an unprecedented increase in whitefly populations, to the extent that they are referred to as "super-abundant". Research efforts since the late 1990s has focused mainly on developing plant resistance to the viral pathogens and paid scant attention to understanding the root causes of disease epidemics or the control of whitefly infestation. Here, we aimed at developing long-term whitefly-control solutions using an in-planta RNA interference (RNAi) approach. First, transcriptome analysis identified candidate genes that play key roles in whitefly biology: osmoregulation, sugar metabolism and transport, symbiosis with endosymbiotic bacteria and detoxification of phytotoxins. Then, fifteen RNAi inverted repeat constructs were produced, designed to target the candidate genes and 140 independent transgenic lines were generated in cassava variety NASE 13. Whole plant bioassays showed insecticidal activity of transgenic plants, reaching 58% lethality for adults within 7 days and 75-90% lethality of nymphs after 25 days, compared to control plants. Target genes were confirmed to be downregulated by up to 2.5-fold in adult whiteflies and nymphs. We used population dynamics modelling to predict the potential of the RNAi technology to control whiteflies under field conditions in East Africa.

Nocturnal migration is a remarkable phenomenon observed in many insect species, including moths. Migratory moths are capable of maintaining precise directional orientation during migration, as demonstrated in both laboratory and field studies, suggesting that they use multiple environmental cues for orientation and navigation. Recent studies on Australian Bogong moths revealed that these animals can use stellar cues and likely the geomagnetic field (in conjunction with local visual cues) to select and maintain population-specific migratory direction. However, the underlying orientation mechanisms used by most other migratory moths are still largely unresolved. Further, it remains unclear whether migratory moths can adjust their orientation using Earths magnetic field parameters for determining their position relative to the goal (i.e. location or map information) - an ability clearly shown in some migratory birds which respond to virtual magnetic displacements by correcting their orientation (experiments when animals are exposed to magnetic cues corresponding to other geographic locations). Here, we present results from virtual magnetic displacement experiments conducted on red underwings (Catocala nupta). In addition, we tested their orientation under simulated overcast conditions and in a vertical magnetic field to get indications whether this species relies on geomagnetic or celestial cues to maintain its population-specific migratory direction. Our results show that (1) red underwings did not compensate for virtual magnetic displacement, indicating the absence of a magnetic map; (2) they remained significantly oriented in the absence of geomagnetic information, suggesting the use of a stellar compass; and (3) there was no evidence of magnetic compass orientation in absence of any visual cues.

RNA viruses are common in tephritid fruit flies including the Queensland fruit fly, Australias most significant horticultural pest. For many their transmission, tissue tropism and load across host development remain unexplored. Yet these factors are important for host biology, ecology and pest management. We investigated Bactrocera tryoni orbivirus (OV), Bactrocera tryoni xinmovirus (XV), Bactrocera tryoni toti-like virus (TLV) and Bactrocera tryoni iflavirus species 2 (IVsp.2) that commonly coinfect B. tryoni laboratory populations. OV and XV transmission was vertical within and on eggs, while TLV transmission was vertical within eggs. IVsp.2 was not detected in eggs but was present in adults; however, IVsp.2 was horizontally transmitted, with viral load increasing with cohabitation time with infected flies. Horizontal transmission was not observed for the other viruses. OV had a similar load across all tissues, while XV was consistently more abundant in ovaries. TLV had a high viral load in the brain whereas IVsp.2 was abundant in the thorax, foregut and midgut. Besides differences in eggs, the viruses were detected in all other developmental stages, but viral load patterns differed: viral load remained constant for TLV, fluctuated for OV and XV, and was low in pre-adult stages and high in adults for IVsp.2. Our findings demonstrate distinct transmission strategies and tissue tropism among the viruses, providing new insights into their epidemiology and role in host biology. Furthermore, contrary to prevailing views that viruses are generally horizontally transmitted, most known RNA viruses of B. tryoni are vertically transmitted affecting the evolution of host-virus interactions.

Iron is an essential nutrient for all types of organisms, including insects and the microbes that infect them. We predicted that insects fed an iron-supplemented diet would accumulate more iron in their hemolymph, and, because infectious microbes acquire iron from their hosts, that this extra iron would increase the severity of bacterial infections. To test this hypothesis, we studied the effects of dietary iron supplementation on infection outcomes in Manduca sexta (tobacco hornworm). Larvae were fed an artificial diet, with or without antibiotics, or the same diets supplemented with 10 mM iron. Control and iron-treated larvae were inoculated with non-pathogenic Escherichia coli or the entomopathogenic Enterococcus faecalis, and bacterial load and larval survival were measured. We found that dietary iron supplementation increased the iron content of hemolymph by approximately 20 fold; however, contrary to our prediction, this increase in iron did not result in an increase in the bacterial load of either E. coli or E. faecalis. The effect of iron supplementation on survival was more complicated. As expected, for larvae inoculated with nonpathogenic E. coli, iron supplementation had no effect. For larvae inoculated with E. faecalis, the effect of iron supplementation depended on whether antibiotics were present in the diet. Without antibiotics, iron supplementation prolonged larval survival; with antibiotics, iron supplementation decreased larval survival. The results of this study do not support the hypothesis that dietary iron supplementation increases infection severity in M. sexta. Instead, the results support the viewpoint that the relationship between dietary iron and infection outcome is complex.

Local temperatures can shape the ability of introduced species to flourish and disrupt novel environments. The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an invasive beetle that threatens ash trees in North America and Europe. To assess the role of temperature on EAB reproduction, we reared groups of adult beetles at one of four temperatures (12, 15, 18, and 21 {degrees}C) and measured reproductive success (laying fertilized eggs and egg hatching). There was no effect of rearing temperature on EAB female lifespans but no eggs laid at 15 or 18 {degrees}C hatched, suggesting these temperatures disrupt the reproductive process of EAB. Females reared at 21 {degrees}C, however, consistently laid eggs that hatched. We then used these results to assess the likelihood of reproductive success over the previous ten years in eight cities in Canada that host EAB. All locations experienced temperatures of [≥] 21 {degrees}C, but the number of hours and the number of days above this critical temperature were highly variable. There were ample opportunities in all locations for EAB to reproduce, but EAB in cooler cities would experience thermal limitations thus slowing the spread of EAB populations.

Dung beetles (Coleoptera: Scarabaeinae) are ecologically important insects, yet genomic resources for this diverse lineage remain limited. Here, we present a high-quality genome assembly for Onthophagus orpheus, an understudied species that is abundant in urban forests in the eastern United States. The assembled genome is highly contiguous and exhibits strong completeness, as assessed by Benchmarking Universal Single-Copy Ortholog (BUSCO) analyses, indicating robust representation of conserved protein-coding genes. Structural and functional annotation recovered a comprehensive gene set consistent with expectations for coleopteran genomes. This genome assembly provides an important resource for future work on the behavioral ecology and population genetics of Onthophagus orpheus, specifically, and Scarabaeinae more broadly.

The greater wax moth, Galleria mellonella, is an increasingly important invertebrate model for infection biology, yet silk extrusion during handling complicates larval injections and hampers survival assessment. Here, we develop and characterise a simple cold-shock method that reliably inhibits silk production without compromising larval viability. Larvae exposed to -20 {degrees}C for 10 minutes completely suppress silk extrusion with 100% survival, representing a substantial improvement over previous chilling approaches. Cold-shocked larvae successfully remained capable of completing development, although pupation and adult emergence were delayed, body weight and fecundity were reduced, and wing deformities were more common. While cold-shock did not alter silk gland morphology, spinneret structure, or fibroin gene expression, confocal imaging revealed pronounced disorganisation of F-actin and -tubulin networks within silk gland cells, indicating cytoskeletal disruption as a likely mechanism underlying silk inhibition. When challenged with Escherichia coli, cold-shocked larvae responded comparably to controls, with survival influenced primarily by feeding status. Together, these findings demonstrate that short-term cold-shock provides an efficient, reproducible, and easy implemented method for preventing silk extrusion in Galleria larvae, markedly improving handling and experimental safety while preserving their suitability as a model host for pathogen research. HighlightsO_LICold-shock at -20 {degrees}C for 10 minutes inhibits silk extrusion. C_LIO_LILarvae survive treatment with no loss of suitability for infection studies. C_LIO_LIDevelopment slows and adult weight, fecundity, and wing quality decline. C_LIO_LISilk glands stay intact; gene expression remains unchanged after cold-shock. Cytoskeletal disruption likely drives the failure of silk secretion. C_LI

Kissing bugs are the primary vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Kissing bugs are exposed to thermal variability, including short periods of heat stress, which can induce mortality or exert sublethal effects. This study investigated Rhodnius prolixus following brief periods of high thermal stress with respect to survival, blood feeding, developmental processes, and T. cruzi infection, with a focus on sublethal effects. Our results demonstrated a significant decrease in survival for R. prolixus at 42 {degrees}C for 8 hours. When exposed to sub-lethal thermal stress (40{degrees}C for 8 hours), blood ingestion (amount and proportion) was reduced after 24 hours of recovery from thermal stress. Among the bugs that fed after 24 hours, molting was not impacted by temperature exposure. The infection rate decreased after heat exposure, likely due to reduced blood volume ingested when feeding 24 hours after heat stress. A week of recovery after exposure to higher temperatures improved feeding and increased infection rates to levels comparable to those of kissing bugs not exposed to thermal stress. Our findings offer insights into how extreme temperature events may influence Chagas disease. Specifically, these studies highlight the need to clarify how temperature, particularly at sublethal levels, interacts with vector biology to alter parasite transmission.

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=118 SRC="FIGDIR/small/700930v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@177a6b4org.highwire.dtl.DTLVardef@6186a3org.highwire.dtl.DTLVardef@ce6196org.highwire.dtl.DTLVardef@168bf43_HPS_FORMAT_FIGEXP M_FIG C_FIG The kangaroo soft tick, Australpavlovskyella gurneyi (Warburton, 1926), is found in sandy depressions ( wallows), under desert shade trees, formed by the activity of the red kangaroo, Osphranter rufus, resting under shade trees (https://youtu.be/AYLoqqPsifc). The field biology of the tick was examined on Moralana Station in arid mid-north, South Australia, between February 1969 and March 1971. The age of kangaroo dung in wallows showed that kangaroos visited wallows regularly during the hot summer and infrequently during the cooler months. All nymphal instars and adults were present at all times of the year in kangaroo wallows, but only a small proportion of the ticks present was trapped on any one occasion. Ticks were abundant in large kangaroo wallows under trees with dense shade, but scarce under smaller trees with sparse shade. The short-lived larvae were present only during spring and early summer, indicating that the long-lived female ticks bred only during spring and early summer. Laboratory tests showed that field-collected adult female ticks entered reproductive diapause from January to August (mid-summer to late-winter). Ticks placed in kangaroo wallows survived for at least one year without food. On Moralana Station, the population of first-instar nymphs increased in summer and subsequently the population of second-instar nymphs increased in early autumn, indicating that a life cycle could be completed in 2-3 years. HighlightsO_LIThe seasonal biology of Australpavlovskyella gurneyi, found in sandy depressions wallows formed by the activity of the red kangaroo, under sparse semi-arid desert shade trees was examined for the first time. C_LIO_LIEngorged ticks placed in kangaroo wallows survived for at least one year without food. C_LIO_LIIn this environment, the entire life cycle could be completed in 2-3 years. C_LI