Abstract Understanding intraspecific variation in reproductive investment is essential for explaining how populations respond to environmental heterogeneity. In amphibians, reproductive effort, measured as testis mass (TM), may be shaped by both individual condition and environmental context, yet their relative contributions remain unclear. We examined the relationships among body condition (BC), environmental gradients, and TM across 11 populations of the marsh frog, Pelophylax ridibundus , in Iran. Using morphological data from 205 adult males and a hierarchical framework, we found that BC was the strongest predictor of TM, supporting a condition-dependent reproductive strategy. However, this relationship varied among populations, which could be grouped into two subgroups differing in baseline TM and in the slope of the BC-TM relationship. Broad-scale climatic variables showed no direct effects on TM after accounting for population structure. Instead, environmental gradients modulated the BC-TM relationship: the positive effect of BC on TM weakened with increasing elevation but strengthened under warmer thermal conditions, whereas annual rainfall had no detectable influence. Linear mixed models outperformed non-hierarchical models, highlighting the importance of population-level structure. Our findings reveal hidden intraspecific heterogeneity in reproductive allocation and caution against relying on ecogeographical expectations when interpreting adaptive responses across environmental gradients.
The brown planthopper (BPH, Nilaparvata lugens (Stal)) is an important pest of rice that causes significant yield loss. To prevent severe economic losses, it is crucial to implement effective sustainable management practices within an integrated pest management framework. Developing effective management strategies requires a thorough understanding of the pest's biology. Hence, the study on the biology and development, N. lugens was conducted under controlled laboratory conditions (25 f 5 degrees C, 70 f 5% relative humidity and 14:10 h light:dark) at ICAR-Indian Institute of Rice Research (IIRR), Hyderabad, Telangana (17 degrees 32 ' N, 78 degrees 39 ' E). The yellowish brown to dark brown one adult female laid an average of 110.8 eggs in cluster ranged from 4 to 16 eggs per cluster by trusting the leaf sheath serially. The highest number of eggs (87.60 %) were laid on leaf sheath of plants followed by midrib (9.20 %) and stem (3.20 %). The average incubation period was 7.20 f 0.86 days with 81.39 per cent hatching. Emerged nymph passed through five nymphal instars to become an adult. The mean durations of the 1st, 2nd, 3rd, 4th and 5th instars were 2.15 f 0.08, 3.35 f 0.10, 4.45 f 0.15, 3.75 f 0.09 and 3.80 f 0.09 days, respectively and nymphal survival was 86 f 1.87 per cent. The pre-oviposition, oviposition and post oviposition period varied from 2-5, 11-14 and 3-6 days, respectively with the mean values of 3.4 f 0.40, 12.2 f 0.58 and 4.8 f 0.58 days, respectively. Adult male was short lived (15.20 days) as compared to female (19.6 days) with 1.0:1.35 sex ratio.
Freshwater amphipods of the genus Hyalella are widely distributed across continental Chile and exhibit marked geographical segregation associated with environmental gradients. The present study analyzed the latitudinal and altitudinal distribution patterns of Chilean Hyalella species using exploratory multivariate approaches based on published occurrence records. Geographic data from 139 records were compiled and analysed using non-parametric statistics and DBSCAN clustering methods. Significant differences among species were detected for both latitude and altitude (P <0.001). The analyses revealed two main distributional assemblages. The first group included H. fossamanchini and H. kochi, species associated with high-altitude saline systems in northern Chile. The second assemblage grouped H. chiloensis, H. franciscae, H. patagonica, and H. simplex, which inhabit temperate and subantarctic freshwater environments in southern Chile. Hyalella costera showed partial overlap with H. chiloensis in coastal environments. The observed patterns suggest that latitudinal and altitudinal gradients are major ecological drivers influencing species segregation in Chilean Hyalella. Furthermore, the Andes may have acted both as a dispersal corridor and as a biogeographical barrier promoting diversification along continental Chile. These findings provide new insights into the geographical structuring of South American freshwater amphipods and contribute to the understanding of regional biogeographical processes in Andean freshwater ecosystems.
The potato tuber moth, Phthorimaea operculella (Lepidoptera: Gelechiidae), is a major pest of potato crop worldwide, causing significant economic losses by infesting tubers both in the field and in storage. Early detection of the pest across its developmental stages is crucial for implementing timely management strategies. In this study, stage-specific sex differentiation was analysed through external morphological examinations at the larval, pupal, and adult stages. In the fourth instar larvae, males were identified by the presence of developing gonads, visible as two dark elliptical structures on either side of the midline on the fifth abdominal segment, which were absent in females. At the pupal stage, males and females were differentiated based on the distance between the genital and anal openings, which was greater in female pupae than in male pupae. In adults, females were identified by a distinct X-shaped marking on the forewings, whereas males exhibited series of black dots during resting posture. Detailed morphological identification including wing venation and genitalia dissection was conducted using eosin staining and ethanol clearing techniques. The study identified reliable morphological characters for distinguishing male and female at the larval, pupal and adult stages, providing practical criteria for stage-specific sex identification for laboratory and taxonomic studies.
This study aims to quantify differences in bird assemblages across three wind farms and along a distance gradient, from wind farms to the edges of Acu & ntilde;a City, Mexico. If wind farms indeed reduce population levels of species most vulnerable to collisions, it is expected that these areas will host generalist species associated with anthropogenic habitats. We conducted 576 transects over two years (2021-2022) to estimate bird assemblages. A total of 147 species were recorded, with the highest richness and abundance at Distance III (the control site nearest to Acu & ntilde;a City), where 103 species were identified, these were mainly synanthropic species. This aligns with the intermediate disturbance hypothesis, suggesting moderate disturbance promotes diversity by increasing resource availability. Contrary to our hypothesis, wind farms showed a higher presence of migratory birds and raptors, contributing to greater taxonomic distinctness. This increased diversity may result from the restricted human access around wind farms, which potentially serve as refuges, protecting these species from disturbances commonly associated with urbanization. These findings emphasize the need to understand how wind farms and urbanization shape biodiversity, particularly in arid ecosystems, where species are often highly specialized and sensitive to environmental change.
