Background: Insecticide resistance among malaria vectors threatens control strategies that are reliant on insecticidal interventions. This study assessed pyrethroid resistance in Anopheles gambiae s.l. populations across Ibadan North (IBN) and Ido LGAs, Oyo State, Nigeria, to elucidate resistance mechanisms and their implications for vector control.

Methods: Larvae and pupae from both LGAs were collected using the dipping method and reared to adulthood in the University of Ibadan Insectary. Molecular identification of An. gambiae complex members was conducted. Three- to five-day-old adult females (n=25/insecticide) were exposed to permethrin, deltamethrin, bendiocarb, and pirimiphos-methyl using WHO susceptibility tests. Synergist assays with Piperonyl Butoxide (PBO) were used to assess the metabolic resistance. kdr (L1014F/S) mutations were detected via allele-specific PCR (TaqMan) at the Nigerian Institute of Medical Research (NIMR), Lagos. Data were analyzed using descriptive statistics and ANOVA (α=0.05).

Results: An. coluzzii predominated in IBN (96.0%) compared with Ido (78.7%), while An. gambiae s.s. was higher in Ido (21.3%) than in IBN (3.3%). An. arabiensis was only recorded in IBN (0.7%). While bendiocarb and pirimiphos-methyl susceptibility was high (98.0 - 100.0%), pyrethroid resistance was widespread (25.0 - 95.0%). PBO restored deltamethrin susceptibility in IBN and one Ido community, suggesting cytochrome P450-mediated metabolic resistance. However, permethrin resistance persisted post-synergist exposure, indicating voltage-gated sodium channel mutations. Only kdr-w (L1014F) was detected, with the allelic frequencies nearing fixation (0.61 in Ido; 01 in IBN).

Conclusion: This study confirms significant pyrethroid resistance in An. gambiae s.l., driven by kdr-w (L1014F) mutations and metabolic resistance. Our findings highlight the urgent need for molecular surveillance and alternative vector control strategies to sustain malaria prevention efforts.

Aphids (Hemiptera: Aphididae) are significant agricultural pests and vectors of plant viruses, making accurate species identification an essential component of pest management and ecological studies. However, DNA degradation in preserved aphid samples presents a challenge for reliable molecular identification. This study aimed to develop family-specific primers for amplifying and sequencing the COX1 barcode region for species identification of old aphid samples. Aphid samples were collected from bucket traps in Christiana, South Africa, between 2006 and 2008, representing 31 species across 21 genera. Morphological identification was conducted initially, and the samples were then stored for long-term preservation in ethanol, prior to primer testing. Universal arthropod primers (LCO1490/HCO2198 and LepF/LepR) failed to amplify the samples because they are old and likely have degraded DNA, highlighting the need to amplify smaller regions of the COX1 gene due to DNA degradation. Family-specific primers were designed based on publicly available mitochondrial COX1 sequences from Aphididae, targeting short overlapping fragments (162–178 bp) of the COX1 gene to reconstruct the complete barcode region. A 294 bp mini-barcode was identified, providing reliable species-level resolution for five aphid species: Acyrthosiphon kondoi, Acyrthosiphon pisum, Macrosiphum euphorbiae, Metopolophium dirhodum, and Tetraneura fusiformis. Species identifications were validated against a curated reference database, achieving high taxonomic resolution. The primers successfully amplified DNA from moderately degraded specimens but were ineffective for severely degraded samples due to DNA fragmentation. This study demonstrates the utility of family-specific primers and the mini-barcode approach for species identification of old aphid samples, offering a robust framework for molecular taxonomy and advancing aphid species identification for ecological research and pest management.

Background: Arboviral diseases, such as dengue, Zika, chikungunya, and yellow fever, are significant public health threats, primarily transmitted by Aedes mosquitoes. Understanding vector infestation levels and breeding site preferences is essential to develop effective control strategies. This study assesses the entomological transmission risk of arboviral diseases by evaluating Aedes mosquito distribution, abundance, and breeding habitats in urban and semi-urban areas of Ibadan, Nigeria.

Methods: A cross-sectional entomological survey was conducted in 5,223 households, with 36,779 water-holding containers examined for Aedes mosquito breeding. Standard infestation indices—the House Index (HI), Container Index (CI), and Breteau Index (BI)—were calculated. The Breeding Preference Ratio (BPR) was used to determine habitat suitability. Data analysis included statistical comparisons of larval and pupal densities between study locations.

Results: This study revealed high infestation levels, with HI values of 71.2% (semi-urban) and 75.2% (urban), CI values of 79.0% (semi-urban) and 67.3% (urban), and BI values of 579.9% and 443.8%, respectively. These indices exceed World Health Organization thresholds, indicating high transmission risk. Artificial containers, particularly tyres, plastics, and vehicle parts, were dominant breeding sites, with BPR values exceeding 1.0 for key habitats. A total of 104,989 larvae and 43,002 pupae were recorded in semi-urban areas, while 78,016 larvae and 34,652 pupae were found in urban locations. Semi-urban areas had higher larval densities, whereas urban sites exhibited greater pupal densities, suggesting differential transmission dynamics.

Conclusion: Targeted vector control interventions, including environmental sanitation and larval source reduction, are essential to mitigate arboviral disease transmission risks in Ibadan and similar endemic regions.

Keywords:

Termites in the genus Macrotermes are important ecosystem engineers, forming the basis of many food webs. Recent research has shown that taxonomic classifications do not fully capture the genetic diversity within this genus, and large areas across Africa and Asia remain unsurveyed.

To bridge this gap, we generated new mitogenomic and DNA barcoding sequence data for Macrotermes specimens collected in seven African countries (Angola, Botswana, Kenya, Ivory Coast, Namibia, South Africa, and Zimbabwe). The new sequences were pooled with the mitogenome and COI sequences available on GenBank and BOLD Systems. Phylogenetic reconstruction was performed for both the mitogenomic and COI sequences separately. The COI dataset was used for species delimitation through the bPTP, p-distance, and ASAP methods.

The neighbour-joining tree showed the most concordance with all of the species delimitation methods, excluding African genetic groups G02 and G17 and Asian genetic groups G28 and G32. Notably, G28 contained 12 taxonomic species, indicating a high level of oversplitting in the Asian clade. In contrast, the African clade shows a high level of cryptic diversity, e.g., as the specimens identified as Macrotermes subhyalinus in previous studies fall into four different genetic groups.

The mitogenome tree showed the African Macrotermes bellicosus in the basal position, and the remaining sequences were divided into African and Asian as sister clades. Although the mitogenome tree does not contain all of the genetic groups identified by the COI analysis, the cryptic diversity in M. subhyalinus is well supported. The Asian genetic group G28 was only represented by two mitogenomes, one of them not identified to the species level; therefore, oversplitting could not be confirmed.

In conclusion, taxonomic problems occur in both the Asian and African clades. This study supports the notion that the genetic and species diversity in Macrotermes has been incorrectly estimated and emphasises the need for taxonomic revision and more comprehensive sampling across under-represented regions of Afro-Eurasia.

Scymnus nubilus Mulsant and Coccinella undecimpunctata L. are two generalist aphidophagous predators abundant in herbaceous habitats. Coccinella undecimpuctata, a larger species, lays its eggs in uncovered clusters, whereas S. nubilus, a tiny species, lays its eggs singly and, possibly, in concealed sites. Reproductive strategies in ladybirds seem to be adaptive, allowing for the co-occurrence of both predators, apparently without interfering with each other. The aim of this study was to characterize the following oviposition strategies in S. nubilus and C. undecimpunctata: daily fecundity, effect of available sites on females’ fecundity and daily pace of oviposition. We hypothesize that the single-egg-laying strategist (i) is more dependent on the availability of concealed sites to oviposit and (ii) lays eggs closer to aphid colonies. We found that different levels of concealability sites allow S. nubilus to increase fecundity. Contrarily to C. undecimpunctata, in the absence of a suitable substrate to conceal their eggs, S. nubilus females refrain from oviposition. Scymnus nubilus prefers to hide its eggs beneath prey carcasses, while C. undecimpunctata is less selective concerning oviposition sites. Scymnus nubilus dilutes its fecundity effort through more oviposition sites and events, while C. undecimpunctata requires one event to lay its clusters. Our results showed that the smaller ladybird is more dependent than the larger one on habitat structural complexity to maximize its fitness and that laying single hidden eggs, mainly during the scotophase, confers a potential adaptive advantage to increase fitness.

The behavioral response of Hyperaspis maindroni to different cassava (Manihot esculenta) varieties was assessed using multi-choice pot culture and olfactometer bioassays. Four cassava varieties, viz. Sree Athulya (resistant), CO3 (moderately resistant), Kunguma Rose (susceptible), and Mulluvadi (highly susceptible), were tested under both healthy and cassava mealybug (CMB)-infested conditions. In the multi-choice pot culture bioassay, H. maindroni exhibited significant variations in its attraction among the cassava varieties. The highest attraction was observed in CMB-infested MVD-1 (11.80 nos.), followed by Kunguma Rose (8.40 nos.), CO3 (5.80 nos.), and Sree Athulya (3.60 nos.). The dual-choice bioassays confirmed that MVD-1 was the most preferred variety, showing the highest attraction percentages when paired with the other varieties (86.60% vs. Sree Athulya, 76.60% vs. CO3, and 65.90% vs. Kunguma Rose). In the olfactometer bioassay, H. maindroni was most attracted to the arm containing the CMB alone (9.10 nos.), followed by healthy MVD-1 (3.40 nos.), Kunguma Rose (2.80 nos.), CO3 (2.40 nos.), and Sree Athulya (1.20 nos.). When testing the CMB-infested leaves, MVD-1 attracted the highest number of H. maindroni (6.90 nos.), followed by Kunguma Rose (5.10 nos.), CO3 (4.30 nos.), and Sree Athulya (3.20 nos.), while the arm with CMB alone had the lowest attraction (0.30 nos.). These findings highlight the strong preference of H. maindroni for CMB-infested MVD-1, emphasizing the role of plant resistance levels in host selection. Understanding these interactions can aid in developing effective pest management strategies for cassava crops.

Spodoptera frugiperda is an invasive pest species in Pakistan mainly damaging the maize crop. The rearing of this pest in the laboratory is crucial as it provides insights into the biology and nutritional requirements of pests that can help develop effective pest management strategies. This study aims to provide a comprehensive understanding of the most suitable diet that can be used in the laboratory to rear Spodoptera frugiperda and its parasitism by Trichogramma chilonis and Telenomus remus. For this purpose, three artificial diets (corn, bean, chickpea) and one natural diet (maize) were evaluated along with the parasitism efficiency of Trichogramma chilonis and Telenomus remus under optimum laboratory conditions. Through the results, it is evident that immature stages of Spodoptera frugiperda had less duration in the chickpea diet (16.94 days) as compared to bean, corn, and maize, while there was no significant difference in the pre-pupal, pupal, and adult durations among all diets. On the other hand, the overall survival rate was highest in the corn diet while the corn-based diet showed the best results regarding fecundity (1283 eggs) as compared to the bean-based diet (863 eggs). In the case of parasitism efficiency, all the diets with 48 hrs of exposure of the eggs to T. remus and T. chilonis had more parasitism than after 24 hrs of exposure. Upon comparing the results, T. remus exhibited the highest parasitism efficiency of 91.5 and 92.3%, respectively, against eggs obtained from the bean and natural diet, while T. chilonis recorded the highest parasitism against the eggs of S. frugiperda reared on chickpea and natural diets (70.2 and 65.9%). From the results, it can be concluded that chickpea was the most suitable diet for the rearing of S. frugiperda, while the least compatible diet was a bean-based diet.

Under proper conditions, green lacewings (Neuroptera: Chrysopidae) larvae show great voracious predatory habits, being an effective biological control species against several pest insects. They are constantly exposed to insecticides as much as their prey on the field, which could impair their lifespan and reproduction, and so far, there are no molecular data available showing the impact of the insecticide pyriproxyfen on testes of Ceraeochrysa claveri. Even when presenting some cellular damage and ultrastructural alterations in the testes cells, this species had already demonstrated tolerance against the insecticide pyriproxyfen, being able to reproduce and maintain their lifespan under lab conditions. Being of great ultrastructural importance, Talin is a protein that connects to the cytoskeleton by the actin and vinculin binding sites and enhances the integrin connection to the extracellular matrix, maintaining the cell structure. This work aimed to evaluate the expression of Talin on testes of C. claveri adults treated with pyriproxyfen during the larval phase by RNA-seq. Newly hatched larvae (0-12h) of C. claveri were individualized, fed on Diatraea saccharalis eggs treated at two concentrations of pyriproxifen (50 mg and 100 mg a.i. L^-1), and compared to a control group (no insecticide intake) for 10 days. After that, all insects fed on eggs with no insecticide until pupation. When adults emerged, 10-day-old males were dissected, with the testes removed and taken for RNA extraction, library construction, and sequencing. The reads were de novo assembled and the genes were annotated by scanning the ORFs for homology. Differentially expressed genes (DEGs) were observed among the groups (50mg vs control; 100mg vs control; and 50mg vs 100mg). RNA-seq results showed that Talin was upregulated in the 50mg vs control and 100mg vs control groups, with both results confirmed by RT-qPCR. These molecular results could help improve Integrated Pest Management (IPM) strategies to better preserve green lacewings on field.

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is a major pest affecting fruit-producing regions in Portugal, with particularly severe impacts in the Oeste region, Algarve, and island territories. The Oeste region is one of the largest apple and pear production areas in the country. These two economically important fruits are often cultivated in adjacent orchards and suffer significant economic losses due to this pest. This study investigated the effects of female age on oviposition preference, larval development, and oviposition periodicity of C. capitata. The first experiment consisted of a laboratory free-choice test to evaluate oviposition preference throughout the adult lifespan between Royal Gala apple (Malus domestica) and Rocha pear (Pyrus communis). The number of oviposition attempts and the number of larvae per fruit were recorded and correlated with key fruit parameters, including colour (ripeness), penetration resistance, and soluble solids content. Fresh fruits were provided daily. The second experiment focused on determining the daily oviposition periodicity under controlled photoperiod conditions (14h light : 10h dark). During the day, mated females (7–9 days old) were exposed to fruits at different intervals: every 3.5 hours during the light phase and one fruit during the dark phase. The number of emerging larvae was recorded at each interval to identify peak oviposition activity. Although data analysis is still in progress, we anticipate that our findings will provide novel insights into C. capitata's reproductive behaviour, with direct implications for pest management strategies in fruit orchards. By the time of the congress, complete results will be available for discussion, offering valuable information for improving monitoring and control techniques in affected regions.

The life cycle of Plasmodium has three phases: the asexual pre-erythrocytic and erythrocytic stages in humans, and the sexual stage in mosquitoes. Although the stages within the human host are well documented, the early bottleneck ookinete stage, occurring within the first 24 hours after the parasite enters the mosquito, remains less understood. Upon taking in blood meal from a parasite-infected host, male and female gametes merge to create a zygote, which eventually develops into a motile and invasive ookinete that penetrates the peritrophic matrix and midgut, while also evading the mosquito's immune responses. The advancement of the parasite aligns with the digestion of the mosquito's blood meal, essential for egg development, facilitated by enzymes. This study investigates the role of carboxypeptidase B (CPB) and peritrophin 48 (Per48) during Plasmodium transmission in Anopheles stephensi, and explores their potential molecular interactions. To evaluate mRNA and miRNA expression profiles in the mosquito midgut tissues, high-throughput sequencing was employed under four experimental conditions: infected (IBF) and uninfected (BF) samples at 18 and 24 h post blood feeding. mRNA analysis revealed significant changes in gene expression, with 1,366 upregulated and 800 downregulated genes at 18 h post-infection, which shifted to 1,780 upregulated and 204 downregulated genes at 24 h. Within this expression profile, both Per48 and CPB were downregulated in infected samples at 18 h, which was confirmed by qRT-PCR analysis. Additionally, miRNA sequencing identified 22 known miRNAs and 12 novel miRNAs, with a rise in the expression of ast-miR-2944 and ast-miR-29a. In silico analysis of miRNA-mRNA interactions suggested that the increased miRNA expression could lead to the downregulation of CPB and Per48. Further, molecular docking showed high binding affinity between Per48 and CPB. This study establishes that Per48 and CPB, in a coordinated manner, influence both digestion and parasite transmission during the early infection phase, offering new insights into vector--parasite interactions and potential targets aimed at blocking transmission.