Female Size Research Articles

Complementary information on the biology of Bactrian camels (Camelus bactrianus) in the Mangistau region of Kazakhstan

The morphometric body parameters of male and female Bactrian camels, Kazakh Bactrian, were studied. Compared to camels of other breeds, the Kazakh Bactrian turned out to be one of the largest camels, having up to 750 kg for males and 690 kg for females, as well as powerful musculature and thick fur. Sexual dimorphism in body size and weight of males and females has been shown. The height at the withers of males was higher than in females by about 3.2 %, oblique length of the trunk by 4.5 %, chest girth by 1.3 %, and tibia girth by 6.6 % higher than in females. The greatest difference was in the live weight of the animals - 23,4 %. A histological study of one of the important internal organs - kidneys - was carried out, which allow camels to adapt to the conditions of waterless deserts. As a result of histological study of the kidneys of Kazakh Bactrians, the following characteristics of camel kidneys were established: the kidney capsule is rather thick (470±12 μm) and is made up of two layers: a layer of collagen fibres (400 μm) and thin (70 μm) inner smooth muscle cells. The relative thickness of the capsule and the presence of the smooth muscle cell layer within it appear to be related to the kidney’s ability to hold high intrarenal pressure while producing highly concentrated urine. The second feature of the Bactrian kidney was that the medullary layer was much thicker than the cortical layer. Their ratio was 1:4. The thick cerebral layer in camels provides relatively long renal tubules and loops of Henle, which are essential for the excretion of concentrated urine.

Determining the generation length and level of morphological and genetic differentiation in the Data Deficient glossy grass skink (Pseudemoia rawlinsoni)

Context Human activities are having a significant impact on biodiversity worldwide, to the extent that we are in the midst of the sixth mass extinction event. Although a substantial proportion of species globally have an elevated risk of extinction, some species are poorly known and there is insufficient information available to adequately assess their risk of extinction. Aims and methods One such species is the glossy grass skink (Pseudemoia rawlinsoni), a widespread but enigmatic lizard species in south-eastern Australia. In order to improve our knowledge of its life history, and particularly its generation length, we examined museum specimens collected from across the range of the species, supplemented with measurements from field-caught individuals. Key results We estimated that the species reaches sexual maturity in 3 years, at approximately 40 mm snout–vent length. Its generation length was estimated as 5 years. Sexual dimorphism was evident, and female body size was positively related to litter size. Although there was no evidence for substantial variation in morphology across the range of the glossy grass skink, a phylogeographic analysis using mitochondrial DNA sequence data (ND4) revealed the presence of seven genetic sublineages (up to 5.1% genetic divergence) within the species. Conclusions The glossy grass skink appears to be a single, but widespread and genetically variable, species. Implications Our study demonstrates how a targeted, multifaceted study can be effective at rapidly gathering data that can be used to contribute vital information to the assessment of extinction risk in Data Deficient species.

Intersexual relationships in mandrills: dominance, sexual conflict and the influence of social integration

The conflict of evolutionary interests between the sexes is commonly imprinted in social dynamics and physical asymmetries between the sexes. In species that live in polygynandrous groups, male-biased sexual size dimorphism often allows males to socially dominate and sexually coerce females. Yet, smaller female size might allow females to escape from males and female philopatry might promote female-female social support allowing females to resist or retaliate against males. The study of such intersexual conflicts is highly relevant in mandrills (Mandrillus sphinx) as they form large polygynandrous groups and exhibit extreme male-biased sexual dimorphism in size and ornaments, higher social integration of females than males, and female coalitions against males. The set up of Mandrillus Project over a decade ago has offered a unique opportunity to study intersexual relationships of mandrills in their natural habitat. Here, I present a synthesis of some recent studies that used the long-term behavioural and life-history dataset of Mandrillus Project and documented patterns of sexual coercion and intersexual dominance in mandrills. These studies show that male mandrills are generally dominant over females and use sexual coercion to increase their mating success. However, female social bonds and social integration permit females to occasionally outrank certain males. Finally, and surprisingly, higher-ranking and more socially integrated females receive higher rates of male sexual coercion, highlighting the need for future research to shed light on the trade-offs between costs and benefits of mandrill sociality.

Assessment of normal renal size in healthy individuals in Pakistan and its influencing factors: A cross-sectional study

Background and objectives. In order to address the need to establish normative benchmark of kidney size in healthy population of Pakistan, this study aimed to assess and quantify the renal sizes in healthy individuals within the Pakistani population using ultrasound imaging. Secondary objectives included examining age-related variations, gender-specific differences, and the correlation between Body Mass Index (BMI) and kidney measurements. Materials and methods. A five-year retrospective investigation of 509 patients undergoing non-renal abdominal ultrasounds at NIKUD Research Hospital employed strict participant criteria, excluding those with diabetes, hypertension, abnormal eGFR, or urinalysis. Ultrasound data was collected from medical record of patients aged 18-80 years without a history or ongoing renal disease, excluding any conditions impacting renal size. Results. In 480 participants meeting stringent health criteria, the right kidney measured 10.45 ± 0.97 cm, and the left kidney measured 10.64 ± 0.95 cm. Age-related variations included increasing renal length until the fifth decade, followed by decline. Gender-specific differences, though statistically non-significant, suggested slightly larger renal sizes in females. A positive BMI and renal length relationship indicated increased sizes in obese individuals. Conclusions. This study establishes renal size benchmarks in a healthy Pakistani population, highlighting demographic factors' role in assessments. Variations across age, gender, and BMI underscore the need for population-specific norms in clinical evaluations.

Psychosocial interventions for suicidal and self-injurious-related behaviors among adolescents: a systematic review and meta-analysis of Chinese practices.

Suicidal and self-injurious-related behaviors (SSIRBs) are a serious public health challenge in China. However, a comprehensive systematic review of psychosocial interventions for SSIRBs among Chinese adolescents has not been performed. To fill this gap, this systematic review and meta-analysis aimed to examine psychosocial interventions for SSIRBs among Chinese adolescents. Eight international (PubMed, EMBASE, Cochrane Library, ScienceDirect, Clinical Trial, CINAHL, PsycINFO, and Web of Science) and four Chinese (Wanfang, SinoMed, CEPS, and CNKI) databases were searched from inception to 31 January 2023. Data extraction and quality assessment were independently conducted by two groups of researchers. Qualitative synthesis and meta-analysis were both used. The initial search yielded 16,872 titles. Of the 649 full texts reviewed, 19 intervention articles focusing on SSIRBs met the inclusion criteria. Thirteen out of the 19 included studies involved cognitive-behavioral therapy (CBT). Seven non-suicidal self-injury (NSSI) studies assessing self-injurious behaviors were included (six short-term studies and three long-term studies). Compared with long-term interventions [-1.30 (95% CI: -1.84, -0.76)], short-term psychosocial interventions had a higher standardized mean difference (SMD) value [1.86 (95% CI: -2.72, -0.99)]. Meta-regression showed an inverse relationship between the treatment response and sample size (slope = 0.068, Z = 2.914, p = 0.004) and proportion of females (slope = 1.096, Z = 5.848, p < 0.001). Subgroup analyses showed that compared with the "less than 1 month" group [-0.494 (-0.783, -0.205)], in the "immediate postintervention" group, the pooled estimate was significantly lower [-2.800 (-4.050, -1.550), p < 0.001]. Our review systematically summarized the key characteristics and effectiveness of existing psychosocial interventions for SSIRBs among Chinese adolescents. Short-term psychosocial interventions for NSSI were significantly effective in reducing self-injurious behavior scores, especially in the immediate postintervention period. More favorable treatment responses could be observed in both male and small samples.

Genome-wide association study meta-analysis of dizygotic twinning illuminates genetic regulation of female fecundity.

Genome-wide association study meta-analysis of dizygotic twinning illuminates genetic regulation of female fecundity.

Intraspecific divergence of sexual size dimorphism and reproductive strategies in a polytypic poison frog

AbstractIntraspecific variation in body size, both among populations and between sexes, is an important factor influencing life-history strategies. This variation might be the response to different environmental conditions, as well as natural and sexual selection, and can result in differences in behavior and reproductive strategies among populations. Here, we use the dyeing poison frog (Dendrobates tinctorius) as a model to investigate how interpopulation variation in body size and sexual size dimorphism affects reproductive strategies. As body size increased, sexual size dimorphism also increased, i.e., females were larger than males, and more so in populations with overall larger frogs. This indicates that there is a stronger selection for body size in females than in males, likely as a response to divergent reproductive investment between the sexes. Females from larger-bodied populations produced larger clutches, but the overall number of froglets produced per clutch did not differ among populations. We discuss potential causes and mechanisms that might be responsible for the observed divergence in body size, sexual size dimorphism, and reproductive strategies among populations that likely represent local adaptations. Our findings demonstrate the importance of cross-population studies, cautioning against drawing general conclusions about a species’ ecology without accounting for intraspecific variation.

The Relationship Between Body Size and Bone Weight (Breast and Thigh) in Kampung Chicken (Gallusdomesticus) Results Third Generation Selection

The aim of this study is to identify the characteristics of body size and shape in kampung chickens, as well as the relationship between body size and meat weight. To achieve this, 200 kampung chicken DOC were directly observed using purposive sampling. Purposive sampling where the chickens were divided into 3 groups of body weight, namely high, medium and low.Body size was recorded at 4, 6, 8, 10, and 12 weeks of age, and the weight of flesh and bone at 12 weeks of age was analyzed using the ttest.The samples used to obtain the weight of meat and bones (breast and thighs) were 35 males and 23 females.The study used principal component analysis to identify body size and shape characteristics for males and females. Regression and correlation analysis were then conducted to determine the relationship and closeness between body size and the weight of flesh and bone.The results of the study showed that the body size and weight of flesh and bone in kampung male chickens aged 12 weeks were significantly higher

Changes in courtship prior to oviposition in chum salmon (Oncorhynchus keta) and male preference for female body size

AbstractMale chum salmon display a courtship behaviour involving an actively “quivering” against female, which is essential for female orgasm. Because generally male prefer larger female, we determined whether the elements of quivering such as the number, the amplitude, and the distance are affected by female body size. Additionally, quivering changes towards oviposition; therefore, we also identified the essential time for the male to succeed in his courtship behaviour. We conducted two experiments to measure quivering parameters: (i) measuring the number and the amplitude of quivering by the acceleration data logger and (ii) measuring the distance between sexes during quivering by observation of recorded video. From the first experiment, there was no significant relationship between the ratio of female‐to‐male body lengths and the number and the amplitude of quivering, while an important relationship between the body length ratio and the distance between sexes from the second experiment. Therefore, we think the distance is more significant than the number or vigour of quivering for male choice, and males quiver more closely to a larger female to increase reproductive success. In addition, when the body length ratio of the sexes is 1.01, the distance during quivering is the shortest. So, there is a possibility that the reproduction of chum salmon is based on size‐assortative mating. And both experiments also showed that male quiver passively as spawning approaches. We suggest that males may not quiver actively for smooth mating as females spawning approaches.

Phenotypic characterization and genetic diversity of indigenous chickens of Jordan in comparison with native and commercial breeds ‎for conservation and breeding purposes

Indigenous chickens of Jordan are facing extinction and need genetic conservation because they were unable to commercially compete in poultry industry because of low genetic ability ‎compared to commercial layers. The study aimed to investigate phenotypic and genetic diversity ‎of village chickens in the Jordan using discriminant analyses procedures to provide a basis for ‎sustainable genetic conservation and utilization program to overcome any possible extinction. The ‎sampled chicken population of 578 one-year old chickens (125 males and 433 females) was ‎phenotypically characterized for 15 biometric and plumage traits from major cities of the three ‎regions; Middle, North, and South. The traits variations within and between breeds were detected ‎statistically by stepwise discriminant and canonical-discriminant of uni- and multivariate analyses. ‎The results showed the sampled population as village chickens in Jordan is comprised of ‎indigenous (Baladi) breed (85%) and few exotic and commercial breeds. The breeds were distinct ‎and differentiated based on phenotypic traits indicating high genetic variability. The major ‎phenotypic traits that showed significant power to differentiate breeds were comb type, body ‎weight, comb size, earlobe color, wattle size, face color and breast size in males and comb type and ‎size, body weight, face and breast size, leg color and wattle size in females. Recent and past ‎crossings, admixture or migration from exotic and commercial breeds were noted. Moreover, low ‎levels of phylogeographic structure were observed across the studied breeds. In conclusion, there is need to conserve the indigenous breed in situ and in vivo for its adaptive gene pool in coming ‎days of persisted climate change and diseases threats.

Larval diet and temperature alter mosquito immunity and development: using body size and developmental traits to track carry-over effects on longevity

BackgroundEstimating arbovirus transmission potential requires a mechanistic understanding of how environmental factors influence the expression of adult mosquito traits. While preimaginal exposure to environmental factors can have profound effects on adult traits, tracking and predicting these effects remains challenging.MethodsUsing Aedes albopictus and a structural equation modeling approach, we explored how larval nutrition and temperature jointly affect development rate and success, female body size, and whether these metrics capture carry-over effects on adult female longevity. Additionally, we investigated how larval diet and temperature affect the baseline expression of 10 immune genes.ResultsWe found that larval development success was primarily determined by diet, while temperature and diet both affected development rate and female body size. Under a low larval diet, pupal wet weight and wing length both declined with increasing temperature. In contrast, responses of the two morphometric measures to rearing temperature diverged when females were provided higher larval nutrition, with pupal wet weight increasing and wing length decreasing at higher temperatures. Our analyses also revealed opposing relationships between adult female lifespan and the two morphometric measures, with wing length having a positive association with longevity and pupal weight a negative association. Larval diet indirectly affected adult longevity, and the time to pupation was negatively correlated with longevity. The expression of eight immune genes from the toll, JAK-STAT and Imd pathways was enhanced in mosquitoes with higher nutrition.ConclusionsOur results highlight deficiencies from using a single body size measure to capture carry-over effects on adult traits. Further studies of larval development rate under varying environmental conditions and its potential for tracking carry-over effects on vectorial capacity are warranted.Graphical

Phenotypic, endocrinological, and metabolic effects of zearalenone exposure and additive effect of heat stress in prepubertal female pigs

Independently, both heat stress (HS) and zearalenone (ZEN) compromise female reproduction, thus the hypothesis that ZEN would affect phenotypic, endocrine, and metabolic parameters in pigs with a synergistic and/or additive impact of HS was investigated. Prepubertal gilts (n = 6–7) were assigned to: thermoneutral (TN) vehicle control (TC; n = 6); TN ZEN (40 μg/kg; TZ; n = 6); pair-fed (PF; n = 6) vehicle control (PC; n = 6); PF ZEN (40 μg/kg; PZ; n = 6); HS vehicle control (HC; n = 7); and HS ZEN (40 μg/kg; HZ; n = 7) and experienced either constant 21.0 ± 0.10 °C (TN and PF) or 35.0 ± 0.2 °C (12 h) and 32.2 ± 0.1 °C (12 h) to induce HS for 7 d. Elevated rectal temperature (P < 0.01) and respiration rate (P < 0.01) confirmed induction of HS. Rectal temperature was decreased (P = 0.03) by ZEN. Heat stress decreased (P < 0.01) feed intake, body weight, and average daily gain, with absence of a ZEN effect (P > 0.22). White blood cells, hematocrit, and lymphocytes decreased (P < 0.04) with HS. Prolactin increased (P < 0.01) in PC and PZ and increased in HZ females (P < 0.01). 17β-estradiol reduced (P < 0.01) in HC and increased in TZ females (P = 0.03). Serum metabolites were altered by both HS and ZEN. Neither HS nor ZEN impacted ovary weight, uterus weight, teat size or vulva area in TN and PF treatments, although ZEN increased vulva area (P = 0.02) in HS females. Thus, ZEN and HS, independently and additively, altered blood composition, impacted the serum endocrine and metabolic profile and increased vulva size in prepubertal females, potentially contributing to infertility.

Genetic and Phenotypic Consequences of Local Transitions between Sexual and Parthenogenetic Reproduction in the Wild.

AbstractTransitions from sexual to asexual reproduction have occurred in numerous lineages, but it remains unclear why asexual populations rarely persist. In facultatively parthenogenetic animals, all-female populations can arise when males are absent or become extinct, and such populations could help to understand the genetic and phenotypic changes that occur in the initial stages of transitions to asexuality. We investigated a naturally occurring spatial mosaic of mixed-sex and all-female populations of the facultatively parthenogenetic Australian phasmid Megacrania batesii. Analysis of single-nucleotide polymorphisms indicated multiple independent transitions between reproductive modes. All-female populations had much lower heterozygosity and allelic diversity than mixed-sex populations, but we found few consistent differences in fitness-related traits between population types. All-female populations exhibited more frequent and severe deformities in their (flight-incapable) wings but did not show higher rates of appendage loss. All-female populations also harbored more ectoparasites in swamp (but not beach) habitats. Reproductive mode explained little variation in female body size, fecundity, or egg hatch rate. Our results suggest that transitions to parthenogenetic reproduction can lead to dramatic genetic changes with little immediate effect on performance. All-female M. batesii populations appear to consist of high-fitness genotypes that might be able to thrive for many generations in relatively constant and benign environments but could be vulnerable to environmental challenges, such as increased parasite abundance.

FEMALE BROODSTOCK SIZE AND MATERNAL EFFECTS ON PROGENY OF Clarias gariepinus (BURCHELL 1822)

Catfish farmers have been enduring having to spawn with very big females at high cost avoiding medium and small sizes. The relationship between female broodstock weight and the growth rate of progeny has been a major concern among catfish producers. To examine the impact of different female broodstock sizes on the reaction to growth of the fish seed, induced breeding of the study fish was done. The experiment was designed a completely randomized design (CRD) made of three treatments replicated three times. The treatment were three categories of weight of broodstocks as Treatment I (1000g (Treatment I or Small size), Treatment II (1500g or Medium size) and Treatment III (2500g or Large size). There was no significant fluctuation in the physico-chemical parameters of the water. There was no significant difference in the fry survival among Treatments (P&gt;0.05). The maternal effect on growth of the study fish was 10.5 weeks of culture as Treatment 11 fingerlings then grew fastest. At the end of 40 weeks culture period there was significant difference (P&lt;0.05) in the final weight of the table fish (1231.67 g, 1156.67g, and 1006.67g, for Treatment 11, Treatment 111, and Treatment 1, respectively). Overall, the results of these growth evaluations showed that the selected group had improved growth performance. Medium sized female broodstock can therefore deliver substantial genetic improvements in induced breeding of the study fish.&#x0D;

Shifting incubation rhythms in response to predation risk and the length of the response in mountain bluebirds

Abstract Parent birds may alter incubation rhythms in response to predation risk but few studies have examined the recovery time immediately after exposure to a predator. Here, we examined incubation rhythms in mountain bluebirds (Sialia currucoides) in response to a simulated nest predator, a taxidermy-mounted squirrel. We used data loggers (iButtons) to measure the recess (off-bout) length, recess rate, and constancy of incubation and found no relationship between incubation rhythms and female age, body size and aggressiveness. Incubating females reacted to the predator by reducing nest visitation rates and increasing recess length but did not change incubation constancy. Instead, constancy was negatively associated with ambient temperature. Changes in incubation behaviour lasted about 48 h before returning to pre-exposure patterns. Our results suggest that modifying incubation rhythms is costly for female birds and the demand to regulate egg temperature efficiently limits the length of behavioural responses to the threat of nest predation.

Incidence of early onset puberty in two-year-old female sea bass, Dicentrarchus labrax L.

The incidence of early onset puberty in female aquaculture fish species is less well known than in males and, it merits to be taken into account in order to properly address its outcomes. The goal of this study was to compare the growth performance and reproductive physiology between 2-year-old female sea bass with early or late onset puberty. Fish from seven fertilized egg cohorts of sea bass were considered. Animals were individually tagged and histologically identified when terminally sampled over the first and second year of life. Ovaries from 1-year-old females were in the chromatin nucleolus (CN) or perinucleolar stage (PN), whereas 2-year-old females showed oocytes in the PN stage and early vitellogenesis (EV) (GSI < 0.7%) or late vitellogenesis (LV) (GSI of 4.45 ± 0.55%). Accordingly, 2-year-old females with less advanced reproductive development were considered as fish with late onset puberty (PN, EV), in contrast to their counterparts that were considered to be fish with early onset puberty (LV). Non-spawning females with early onset puberty were observed. The early onset puberty occurred in 18.1 ± 6.4% of fish in the population, although it was variable among the cohorts. Body size of early pubertal females was usually larger than that of fish with late onset puberty (28.7% heavier in weight and 7.9% greater in fork length). Differences in circulating levels of the insulin-like growth factor-1 (Igf-1) and those of 17-beta estradiol (E2), follicle-stimulating hormone (Fsh) and vitellogenin (Vtg) one year before spawning, significantly contributed to explaining the total variance associated with the early onset puberty in this species. This study provides valuable information on the interplay that these factors might have at the onset of early puberty in fish and, in turn, its potential use as key indicators of this trait in the female sea bass.

Using advances in technology to develop sizing methodology for women’s sports compression garments

ABSTRACT The aim of this study was to evaluate the suitability of current sizing systems adopted by brands, for an athletic female population and try to identify areas of improvement in current sizing and grading methods used. This information can be used to engineer accurately fitting lower-body sports compression leggings for the target demographic. Size and shape data of sixty-three athletic females was collected using 3D body scanning. The data was compared to size charts of three commercially available sports compression leggings manufactured by different brands as well as Alvanon's UK sizing and grading standards. Results show that athletic females are not catered for by current products. 28 women (44.44%) fell between sizes for at least one measurement across the three brands. Participant's measurements indicate differing body shapes to the standard ‘hourglass’ shape presented by the Alvanon UK sizing standards, used by companies as a basis for their sizing systems.

Assessment of biomass culturing effectiveness of Artemia in tarpaulin tank in Ho Chi Minh City

The study was carried out to determine the suitable stocking densities and harvesting methods, and to evaluate the economic efficiency of Artemia biomass culturing in tarpaulin tanks in Ho Chi Minh City. The experiment consisted of 8 treatments arranged in a completely randomized block design with 3 replicates of 2 stocking densities (M1: 1,500 &amp; M2: 2,000 individuals/L) and 4 harvesting frequencies (T1: 1 day/time - 10%, T3: 3 days/time - 30%, T5: 5 days/time - 50% and T14: 14 days collecting 100% amount of Artemia biomass in the tank). The study results showed that the average size of males and females ranged from 9.12 - 9.55 mm and 9.84 - 11.01 mm, respectively. At day 14, the survival rate at a density of 1,500 individuals/L accounted for 63.68 ± 2.50% which was statistically significant (P &lt; 0.05) compared to the density of 2,000 individuals/L (60.95 ± 1.39%). The mean fecundity of female Artemia ranged from 70 to 72 embryos/female and tended to increase gradually from 92 to 101 embryos/female. The harvesting frequency affected Artemia population composition, density and biomass yield. After 29 days, the T3M1 treatment yielded the highest biomass (3.33 ± 0.39 kg/m3) and the most optimal profit with 225.53 ± 9.08 thousand VND/kg. The treatment DCM2 gave the lowest yield (1,22 ± 0.27 kg/m3) with a profit of 78.04 ± 58.58 thousand VND/kg.

New insight into drivers of mammalian litter size from individual‐level traits

The digitization and open availability of life history traits measured directly from individuals provide a key means of linking organismal function to environmental and ecological contexts at fine resolution. These linkages play a critical role in understanding trait‐mediated response to global change, with particular need to resolve them for taxa that are secretive and hard to monitor, like most mammals. In this study, we use digitized museum specimen and census data to document how climate and body size each shape a key life history trait – litter size – in 39 small mammals across North America. We employ mixed models to test associations between litter size, climate and body size, with a focus on joint estimation of inter‐ and intraspecific trends. Among species, no single climate predictor explained a large amount of litter size variation. Instead, interactions between temperature‐related (continentality, solar irradiation) and moisture‐related (annual precipitation, relative humidity) indices, along with body size, exert a stronger influence on litter size. We observed maximal litter sizes for species inhabiting seasonal or xeric regions under conditions of increased moisture availability, or conversely, mesic or aseasonal regions under conditions of reduced moisture availability. These patterns are consistent with primary productivity as a mechanistic driver of litter size. At the intraspecific level, litter size responds to continentality and temperature‐related indices experienced by populations, but is most strongly shaped by body size of individual females. We also find evidence of phylogenetic covariation in these intraspecific trends. Our study demonstrates how life history traits assembled from individual‐level biodiversity records improve precision and granularity of ecological studies, help to parse among‐ and within‐species trends, and foster improved understanding of tradeoffs between energetic supply and demand (e.g. reproduction) in wild mammals.

Comparison of home range size, habitat use and the influence of resource variations between two species of greater gliders (Petauroides minor and Petauroides volans).

Knowledge of the spatial requirements of a species is fundamental to understanding its environmental requirements. However, this can be challenging as the size of a species' home range can be influenced by ecological factors such as diet and size-dependent metabolic demands, as well as factors related to the quality of their habitat such as the density and distribution of resources needed for food and shelter. Until recently, the genus Petauroides was thought to include only a single species with a widespread distribution across eastern Australia. However, a recent study has provided genetic and morphological evidence supporting Petauroides minor as a distinct northern species. Previous studies have focused on the ecology of P. volans, but there has been inadequate research on P. minor. Data on home range and habitat use were obtained for both species using a combination of techniques including GPS collar locations, radiotelemetry, and spotlighting and comparisons were made using consistent methodology. Home range sizes of P. minor (4.79 ha ± 0.97 s.d., KUD .95) were significantly larger than those of P. volans (2.0 ha ± 0.42 s.d., KUD .95). There were no significant differences between male and female home range sizes in either species. Both species showed site-specific preferences for tree species and for larger diameter trees for both forage and shelter. Tree size and biomass/ha were significantly greater in the P. volans study sites than the P. minor study sites and there was a negative correlation between home range size and eucalypt biomass. Larger home range size is likely driven by the substantial differences in biomass between northern (tropical) and southern (temperate) eucalypt-dominated habitats affecting the quality and quantity of resources for food and shelter. Understanding landscape use and habitat requirements within each species of Petauroides can provide important information regarding limiting factors and in directing conservation and management planning.