Asian Journal of Research in Zoology

Spatial Morphometric Differentiation of Catfish Sperata seenghala (Sykes, 1839) across Different Stretches of the Gomati River, Tripura, India

Dipak Das — Sat, 05 Sep 2026 00:00:00 +0000

Background: Morphometric differentiation occurs in fishes within the same ecosystem or river when populations experience distinct microhabitats due to the dynamic nature of water physicochemical characteristics, such as water flow, food availability, and predation. It may offer survival benefits under changing environmental conditions to a certain extent.

Aim: The study was conducted to compare five populations and both sexes of Sperata seenghala (Sykes, 1839) in the Gomati River, Tripura, India, using 30 morphometric assessment criteria.

Method: The morphometric data used to quantify shape variation were analysed using the coefficient of variation (CV), principal component analysis (PCA), and UPGMA clustering.

Results: PCA performed on the morphometric data accounted for total variations of 78.62% (59.181% + 19.448%) and 95.73% (86.649% + 9.085%) in the first two principal components (PC1 and PC2) for male and female populations, respectively. The UPGMA dendrogram showed that, among males, the Maharani and Kakraban populations shared the most similar characteristics, whereas Sonamura was the most morphologically distinct population compared with the other populations. Among females, the Jatanbari and Amarpur populations shared the most similar characteristics, while Sonamura was an outlier compared with all other groups.

Conclusion: The findings provide insights into distinct morphological variation among populations of both sexes, demonstrating morphometric differentiation across five geographically distinct stretches of the Gomati River in Tripura. Further study is required to link these patterns with environmental variables and to assess adaptation to changing habitats through phenotypic plasticity and natural selection.

Crop Pest Inventory and Preliminary Evaluation of Plant-Based Repellents in Guwahati, Assam, India

Pratham Dasgupta, Shabnam Sultana — Wed, 09 Sep 2026 00:00:00 +0000

Agricultural production and household food storage in Assam face persistent challenges from insect pests, while the use of accessible plant-based materials for pest management remains insufficiently documented at the local level. The present study aimed to document insect pests associated with selected stored grains, pulses, and fruit and vegetable crops in and around The Assam Royal Global University, Guwahati, Assam, and to obtain exploratory mortality observations following exposure of the rice weevil, Sitophilus oryzae, to two self-prepared plant-based formulations. Field surveys and household-level observations were conducted to document pest occurrence, followed by preliminary identification based on observable morphological characteristics and photographic comparison using the INSECT ID application, with nomenclatural cross-reference through the Catalogue of Life. Three plant-based formulations were prepared using Lantana camara, dry chili, clove, methanol, etc.; two formulations, LR1 (Lantana-Methanol) and LR2 (Lantana-dry Chilli-Clove), were subjected to exploratory mortality observations against S. oryzae over a seven-day period. A total of 47 deaths were recorded following LR1 exposure, with 3 individuals remaining alive at the final observation, while 33 deaths were recorded following LR2 exposure, with 17 individuals remaining alive. FT-IR analysis of the two tested formulations provided preliminary information on their functional-group profiles. The study documents locally observed crop-associated pests and provides preliminary mortality observations for two self-prepared formulations. However, untreated and solvent controls, biological replication, and concentration-response testing were not included in the original bioassay; therefore, the observed mortality cannot be attributed specifically to the plant-derived constituents or used to establish formulation efficacy. Similarly, the preliminary taxonomic identifications were not independently verified using standardised taxonomic keys or expert confirmation. The findings should therefore be regarded as baseline observations that warrant validation through controlled, replicated, and taxonomically verified future studies.

Behavioral Responses of the Freshwater Air-Breathing Fish Channa punctatus to Prolonged Exposure to Rogor (Dimethoate) under Laboratory Conditions

P. K. Azad, D. N. Choudhary — Wed, 09 Sep 2026 00:00:00 +0000

Behavioural responses can provide sensitive indicators of contaminant stress in fish, including exposure to organophosphate pesticides. This laboratory study characterised the time course of behavioural responses in the freshwater air-breathing fish Channa punctatus exposed to nominal concentrations of Rogor (30% EC dimethoate) corresponding to fractions of a previously reported 96-h LC₅₀of 0.74 mL/20 L. Fish were assigned to four groups: control (A), 1/5 LC₅₀ (0.148 mL/20 L; B), 1/3 LC₅₀ (0.247 mL/20 L; C), and 1/2 LC₅₀ (0.370 mL/20 L; D), with three replicate aquaria per group and 10 fish per aquarium. Opercular movement, surfacing frequency, feeding response, qualitative locomotor abnormalities, and stress-related behaviours were recorded at 48, 72, and 96 h and at 10, 20, 30, and 40 days. The reported observations showed relatively transient changes in Group B and more persistent respiratory, feeding, locomotor, and stress-related abnormalities in Groups C and D. No mortality occurred in Groups A or B; two deaths occurred in Group C and four in Group D during the prolonged exposure. Interpretation of treatment effects is necessarily cautious because exposure concentrations were nominal rather than analytically verified and the recorded mean water temperature was higher in the control group than in the treated groups. Within these limitations, the findings indicate that prolonged exposure to LC₅₀-derived fractions of Rogor was associated with progressively greater behavioural disturbance and mortality at the higher nominal concentrations. Long-duration behavioural observations may therefore complement conventional acute toxicity endpoints when supported by rigorous exposure verification and experimental-unit-aware analysis.

Assessment of the Effect of Wild Animals on Cocoa Farms in Boki Local Government Area, Cross River State, Nigeria

Ovat Innocent Ovat — Fri, 11 Sep 2026 00:00:00 +0000

This study assessed the effects of wild animals on cocoa farms in Boki Local Government Area, Cross River State, Nigeria, with emphasis on the species associated with farm damage, the nature and extent of damage, farmers’ experiences of cocoa-wildlife conflict, and locally relevant management responses. A descriptive survey design was used to collect quantitative and qualitative data through structured questionnaires, in-depth interviews, and field observations. Eighty cocoa farmers from four communities participated in the study. The majority of respondents were male (91.25%), and the largest educational category comprised respondents with no formal education (35%). Mammals constituted most of the wild animals identified as damaging cocoa farms, with affected plant parts including pods, bark, trees, beans, leaves, and roots. More than half of respondents (53.75%) reported observing wild animals on or near their cocoa farms, while 57.5% agreed that rodents, monkeys, bats, insects, and snakes attacked cocoa farms. Loss of cocoa pods (50%) was the most frequently reported form of conflict. Lack of knowledge (36.25%) and local taboos (28.75%) were prominent management challenges. Training and workshops (31.25%) and community awareness programmes (25.00%) were the principal forms of support considered useful, whereas 51.25% of respondents considered local authorities ineffective in managing cocoa-wildlife conflicts. The findings support locally adapted, non-lethal management approaches that integrate cocoa production with wildlife conservation and sustainable landscape management.

Mitochondrial DNA in Animal Systematics, Population Genetics, and Biodiversity Research: Applications, Limitations, and Emerging Perspectives: A Narrative Review

Ganesh H. Fadake — Sat, 05 Sep 2026 00:00:00 +0000

Mitochondrial DNA (mtDNA) remains a widely used molecular resource in animal systematics, phylogeography, population genetics, conservation biology, and biodiversity assessment. Its high cellular copy number, compact genome, and informative variation across loci such as cytochrome c oxidase subunit I, NADH dehydrogenase genes, 12S and 16S rRNA, and the control region support applications ranging from species identification to population-level inference. This narrative review synthesises the principal applications of mtDNA in phylogenetic reconstruction, phylogeography, population genetics, DNA barcoding, aquatic biodiversity monitoring, environmental DNA metabarcoding, conservation, and mitogenomics. It also examines major biological and analytical limitations, including maternal inheritance, heteroplasmy, nuclear mitochondrial DNA segments, introgression, mitochondrial capture, incomplete lineage sorting, natural selection, inherited symbionts, and mito-nuclear discordance. Particular attention is given to the influence of reference-library quality, marker choice, sampling design, and analytical quality control on interpretation. The review further considers bioinformatic workflows, historical DNA, next-generation sequencing, population mitogenomics, and emerging machine-learning applications, while emphasizing that analytical tools cannot compensate for weak sampling, contamination, or incomplete reference data. Complete mitochondrial genomes can improve character sampling and phylogenetic resolution, but they remain linked and therefore retain the inheritance constraints of a single mitochondrial lineage. Accordingly, mtDNA is most informative when its results are interpreted with nuclear genomic, morphological, ecological, and geographic evidence. An integrated approach can reduce overinterpretation and support more robust assessments of evolution, taxonomy, conservation, and biodiversity.

A Critical Literature-Based Checklist of Spider Diversity in Central India and Adjacent Border Districts

Urwashi Chandrakar, Ayantika Pal — Mon, 07 Sep 2026 00:00:00 +0000

Spider distribution records in central India are dispersed across taxonomic papers, regional surveys, institutional reports, and state-level checklists. This literature-based review consolidates records from Madhya Pradesh and Chhattisgarh together with selected districts of neighbouring states that share boundaries with these two states. A structured search of scholarly databases and traceable institutional literature was conducted for publications available through 31 July 2026. Taxon names were reconciled conservatively against the World Spider Catalog, Version 27, accessed on 20 August 2026, and relevant specialist revisions. The source matrix contained 704 literature-derived taxon rows. After consolidation of duplicate accepted names and explicit retention of uncertain records, the final checklist comprised 689 records. These included 538 accepted species in 178 genera and 35 families; the complete evidence table included 39 families when genus-level, unresolved, doubtful, distributionally discordant, and excluded records were also considered. Additional categories comprised 87 genus-level records, four tentative identifications, six nomina dubia, one unavailable name, 23 unresolved historical names, 23 records requiring distributional verification, and seven unsupported or indeterminate records. Qualifying literature was available for 36 of 52 districts in Madhya Pradesh, four of 33 districts in Chhattisgarh, and 22 of 42 selected adjacent border districts. The checklist therefore provides a transparent baseline of documented occurrence rather than an estimate of standardised regional richness. The principal priorities are specimen-linked taxonomic verification and standardised, multi-season surveys in poorly represented districts.