Oxyopidae Research Articles

Peptide Toxin Diversity and a Novel Antimicrobial Peptide from the Spider Oxyopes forcipiformis

Spider venoms are emerging as a rich source of bioactive peptide toxins with therapeutic potential. Lynx spiders of the genus Oxyopes are small, cursorial hunters that employ complex venom to subdue arthropod prey. However, extracting crude venom from these diminutive arachnids poses significant challenges. This study presents a transcriptome analysis of venom glands from an undescribed Oxyopes forcipiformis species, revealing 339 putative protein and peptide toxin sequences categorized into seven functional groups. The venom composition was dominated by membrane-active peptides (40.71%), venom auxiliary proteins (22.71%), neurotoxins (15.63%), channel active peptides (7.08%) and uncharacterized components (13.87%). Additionally, phylogenetic analysis of 65 disulfide-bond-rich peptides yielded six distinct families based on sequence homology and cysteine framework. Finally, a novel antimicrobial peptide, GK37, was identified using in silico and homology analyses. Our data suggested that GK37 presented significant antibacterial activity against Gram-positive bacteria Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 1.552 µM by disrupting bacterial membranes. At 4× MICs, GK37 almost showed no hemolytic activity on blood cells or toxicity against Hek293T cells. Our findings provided a basis for targeted studies of the diversity and pharmacological effects of lynx spider peptide. We elucidated a valuable high-throughput approach for obtaining proteins and peptides from small-group spiders.

New observations on prey scarab beetles and host plants of the green lynx spider, Peucetia viridans (Hentz, 1832) (Araneae: Oxyopidae) in Oaxaca, Mexico

ABSTRACT Peucetia viridans (Hentz), commonly called the lynx spider, is an important predator with a diet that encompasses a wide variety of insects and arachnids, including cannibalism. Although several studies that address aspects related to its ecology and behaviour have been carried out, there is a notable lack of studies focused on the recording of its prey and hosts. This information gap is particularly evident regarding the interaction of the spider with beetles belonging to the family Scarabaeidae. To contribute to the knowledge of the feeding habits and host preferences of P. viridans, observations were made in two localities of the Valles Centrales region of Oaxaca, Mexico. Lynx spiders were observed on Croton ciliatoglandulifer Ortega, Lantana camara Linnaeus, Solanum mitlense Dunal, and Wigandia urens (Ruiz and Pav.) Kunth. Spiders utilise these plants as shelter and to ambush their prey, thereby reducing herbivore populations and protecting the plants. In return, the plants provide the spiders with prey and floral and extrafloral nectaries as food sources. Therefore, spiders and plants have a facultative mutualistic relationship, whereas the relationship between spiders and herbivores is antagonistic. For the first time Diplotaxis trapezifera Bates, Macrodactylus fulvescens Bates, Paranomala discoidalis (Bates), Strigoderma costulipennis Bates, Strigoderma sulcipennis Burmeister, and Euphoria pulchella (Gory and Percheron) as prey, and Wigandia urens, Lantana camara and Solanum mitlense as host plants are recorded. A checklist of host plants for P. viridans is given. Overall, these new observations highlight the importance that tritrophic interactions (plant–herbivore–natural enemy) have in wild systems, which are essential for maintaining ecological balance.

Taxonomic notes on two poorly known lynx spider species from India (Araneae: Oxyopidae)

Taxonomic notes on two poorly known lynx spider species from India (Araneae: Oxyopidae)

Integrative species delimitation and five new species of lynx spiders (Araneae, Oxyopidae) in Taiwan.

An accurate assessment of species diversity is a cornerstone of biology and conservation. The lynx spiders (Araneae: Oxyopidae) represent one of the most diverse and widespread cursorial spider groups, however their species richness in Asia is highly underestimated. In this study, we revised species diversity with extensive taxon sampling in Taiwan and explored species boundaries based on morphological traits and genetic data using a two-step approach of molecular species delimitation. Firstly, we employed a single COI dataset and applied two genetic distance-based methods: ABGD and ASAP, and two topology-based methods: GMYC and bPTP. Secondly, we further analyzed the lineages that were not consistently delimited, and incorporated H3 to the dataset for a coalescent-based analysis using BPP. A total of eight morphological species were recognized, including five new species, Hamataliwa cordivulva sp. nov., Hamat. leporauris sp. nov., Tapponia auriola sp. nov., T. parva sp. nov. and T. rarobulbus sp. nov., and three newly recorded species, Hamadruas hieroglyphica (Thorell, 1887), Hamat. foveata Tang & Li, 2012 and Peucetia latikae Tikader, 1970. All eight morphological species exhibited reciprocally monophyletic lineages. The results of molecular-based delimitation analyses suggested a variety of species hypotheses that did not fully correspond to the eight morphological species. We found that Hamat. cordivulva sp. nov. and Hamat. foveata showed shallow genetic differentiation in the COI, but they were unequivocally distinguishable according to their genitalia. In contrast, T. parva sp. nov. represented a deep divergent lineage, while differences of genitalia were not detected. This study highlights the need to comprehensively employ multiple evidence and methods to delineate species boundaries and the values of diagnostic morphological characters for taxonomic studies in lynx spiders.

Faunistic and diagnostics of predaceous spiders in rice ecosystem under Terai region of West Bengal

Aim: Analyzing the community structure of predatory spider fauna in rice ecosystems to facilitate conservation biological control and sustainable pest management programmes. Methodology: The spiders were collected from rice field with cultivated variety (MTU-7029) during both Kharif and Rabi seasons at different rice growth stages. The spiders collected by various sampling methods such as direct catch in polythene carry bags, ground collection and foliage collection were kept in collection bottles and killed by inserting a strip of cotton dipped in chloroform and transferred separately on a white sheet of paper. Thereafter, using a stereo zoom microscope (ZEISS Stemi 508), the spiders were sorted, separated, counted, identified based on the available keys and literature described by Tikader (1987) and Barrion and Litsinger (1995). The unidentified samples were sent to the Zoological Survey of India, Kolkata for authorized identification. Results: In total, sixteen different species of predatory spiders belonging to six families of order Araneae and representing four functional/foraging guilds were identified in the rice ecosystem of Sub-Himalayan Terai region of West Bengal. These included Lycosa pseudoannulata Boesenberg & Strand and Arctosa tanakai Barrion & Litsinger; Oxyopes lineatipes C.L. Koch, Oxyopes javanus Thorell and Oxyopes salticus Hentz; Bianor sp. and Hasarius adansoni Audouin, while the family Thomisidae was represented by a single species Thomisius sp. All these eight species constituted the non web former group of spiders. The web weaving spiders recorded were Tetragnatha maxillosa Thorell, Tetragnatha mandibulata Walckenaer. Tetragnatha javana Thorell, Leucage decorate Walckenaer, Leucage celesbesiana Walckenaer and Neoscona theisi Walckenaer, Neoscona mukerjei Tikader, Araneus sp. Interpretation: The lynx spiders (Oxyopidae) were found to be the most dominant group by individual numbers, followed by the wolf spiders (Lycosidae), however, considering the species richness, the long jawed spiders (Tetragnathidae) were in large number with five different species. Good agricultural practices along with habitat diversification of landscapes are imperative for enhancing the predation by rice field spiders. Key words: Dominance, Foraging guilds, Predatory spiders, Rice, Species richness, Terai region

Seasonal Abundance and Feeding Behaviour of <i>Oxyopes birmanicus</i> Thorell on Tea Mosquito Bug <i>Helopeltis theivora</i> Water House

The Burmese lynx spider, Oxyopes birmanicus Thorell (Araneae: Oxyopidae) is one of the endemic and entomophagous predatory arthropod species in India. This present study describes the seasonal abundance, vertical distribution, and feeding behaviour of O.birmanicus on nymph (4 th /5 th instar) and the adults of the tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae) under laboratory conditions. The seasonal abundance of the O. birmanicus spider was considerably high from June to November and low from January to April. The abundance of O. birmanicus significantly correlated with the TMB infestation percentage. In a vertical distribution study, the O. birmanicus spider largely preferred the top level of the tea bush, the observed population was shared by the top and middle levels with 76% and 24% respectively. The feeding potential of the female O. birmanicus spider was significantly higher than the male and egg-guarding female. Both, male and egg-guarding female O. birmanicus showed on-par feeding efficacy. The study found that O. birmanicus was an efficient predator against TMB and the results may be useful in developing an integrated pest management strategy for TMB.

A new species of Hamataliwa (Araneae: Oxyopidae) from Western Ghats, India

A new species of lynx spider genus Hamataliwa Keyserling is described from the Western Ghats, one of the world’s biodiversity hotspots. Female of the new species is illustrated, and distribution has been mapped.

Diversity and population dynamics of predatory fauna in the brinjal ecosystem under IPM and non-IPM situations

The study was conducted to assess and document the diversity, abundance of insect predators and its relationship with weather parameters in brinjal ecosystem at Horticultural farm, Horticultural College and Research Institute, Thiruchirapalli. The study has shown that the Lynx spider, Peucetia viridana was the dominant species with relative abundance of 19.04% and 20.39%, respectively in IPM and non-IPM plots. Among the coccinellid predators, Brumoides sutularis was recorded as the predominant species with relative abundance of 13.82% and 20.42% in respective IPM and non - IPM plots. Simpson and Shannon Weiner index of the present study showed that the natural enemies’ population was abundant in intercropped (IPM) plot than in the non - IPM plot. Spider population fluctuated throughout the cropping period and exhibited positive correlation with maximum temperature (r = 0.097 to 0.465), morning relative humidity and negative correlation with rainfall (r = - 0.078 to - 0.395) exhibiting that the population buildup was good at high temperature. Similarly, correlation coefficient obtained for coccinellids also exhibited that the maximum temperature (r = 0.057 to 0.443), minimum temperature and morning relative humidity had positive effect on the population. Whilst, wind velocity and rainfall (r = - 0.020 to - 0.990) implicated negative effect on the population of coccinellid predators. The neuropteran and heteropteran predators showed negative correlation with maximum temperature, evening relative humidity and positive correlation with minimum temperature, morning relative humidity and rainfall.

Oophagy in spiders: consumption of invertebrate and vertebrate eggs

In this paper, we present an update on our knowledge on egg predation (oophagy) by spiders. Based on a survey of 233 reports, ghost spiders (Anyphaenidae), lynx spiders (Oxyopidae), jumping spiders (Salticidae), and yellow sac spiders (Cheiracanthiidae) were the most prominent groups of spiders engaged in oophagy. Around 75% of the reports referred to the consumption of lepidopteran and spider eggs worldwide. Another 10% referred to the consumption of eggs/embryos of anurans – especially predation upon embryos of glass frogs (Centrolenidae) by spiders from the families Anyphaenidae and Trechaleidae in the Neotropics. The remaining 17% included rare instances of feeding on eggs of coleopterans, dermapterans, dipterans, heteropterans, homopterans, hymenopterans, acarids, neuropterans, opilionids, and squamates. Our study demonstrates that oophagy in spiders is much more widespread than previously thought, both geographically and taxonomically. The finding that spiders feed on eggs/embryos from so many different invertebrate and vertebrate taxa is novel.

Understanding spatially complex cryptic coloration in the green lynx spider Peucetia viridans

AbstractMany species are thought to use cryptic coloration to evade predators or catch prey. However, colour patterns are historically difficult to document and compare when coloration is continuous and spatially complex. The authors studied colour variation in the green lynx spider, Peucetia viridans, a sit‐and‐wait predator often found in the tops of inflorescences feeding on pollinators. Spiders were collected from three distinct plant species that provided different original colour backgrounds and photographed under standard lighting and background. A novel colour analysis method (Colormesh) was used to quantify spatially explicit contributions of red, green, and blue along the spider abdomen from digital photographs. Spiders collected from green backgrounds were found to have significantly greater contributions of green abdomen colours; red and blue body colours showed no significant correlation with spider background. This is the first study of colour‐matching in a natural population of this wide‐spread generalist predator and also demonstrates a novel method for quantifying complex, continuous colour patterns.

Occurrence of spider fauna in relation to biotic and abiotic factors in rice eco system

Occurrence of spider fauna in relation to biotic and abiotic factors in rice eco system was studied at Central Research Station and Department of Entomology, Odisha University of Agriculture and Technology, Bhubaneswar, during Kharif 2018-2019 and kharif 2019-20. A total of 622 spider specimens belonging to 9 species, 7 genera and 4 families were collected from rice ecosystem under Bhubaneswar conditions by various sampling methods. The four recorded spider families in order of abundance were Araneidae < Tetragnathidae < Lycosidae < Oxyopidae. Araneidae and Tetragnathidae were the two dominant spider families as four species viz., spotted orb weaver, Neoscona elliptical (Tikader and Bal), grass cross spider, Argiope catenulate (Doleschall), orb weaving spider, Araneus sp, Larinia orb weaver, Larinia sp were recorded under family Araneidae where as three species viz., big jawed spider, Tetragnatha mandibulata (Walckenaer), long jaw spider, Tetragnatha maxillosa (Thorell), tailed tetragnathid spider, Tetragnatha javana (Thorell) were recorded under family Tetragnathidae. The families Lycosidae and Oxyopidae were represented by single species viz., wolf spider, Pardosa pseudoannulata (Boes and Strand) and lynx spider, Oxyopes bharatae (Gajbe), respectively. All the nine spider species recorded were active at vegetative stage, reproductive stage and ripening stage of the crop. Maximum population of spider (1.40/ m2) was noticed at reproductive phase during 45th std week (Nov 4-10) synchronizing with the peak activity period of BPH (18/hill) and WBPH (17/hill). A highly significant positive correlation existed between population of spiders irrespective of species and the incidence of leaf folder, WBPH, BPH and gundhi bug in both the seasons. Spider population regardless of species showed non significant negative correlation with minimum temperature, morning relative humidity, evening relative humidity and rainfall.

Population dynamics of stem fly and defoliator pests of soybean and their natural enemies in relation to weather parameters

The field experiment was carried out at Polasa Farm, Regional agricultural research station Jagtial during the Kharif, 2014-15 and 2015-16. Study about pre dominant lepidopteran insect –pests in soybean crop noticed that the tobacco cut worm, (Spodptera exigua Hubner), green semi looper(Crysodexis acuta Walker), and tobacco caterpillar (Spodoptera litura Fab) along with stemfly, (Melanagromyza obtusa Zehnter) as non lepidopteran pest were noticed at various growth stages of cropgrowth. The peak activity of stem fly (37.84%) was observed during 37th standard week per meter row) for the year 2014 and for the year 2015 to a maximum infestation of 35.70 per cent during 30th std.week. The peak activity of caterpillar pests i.e., S. litura (7.6 larvae per meter row) for the year 2014 was observed during 34th std.week and for the year 2015 (12.4 per meter row during 36th std.week and C. acuta (0.7 larvae per meter row) during 36th std. week for the year 2014 and for the year 2015 (2.20 larvae/mrl on 37th std week. S. exigua (1.6 larvae per meter row) for both the years 2014 and 2015 was observed during 32th std.week Among the natural enemies, one predators namely, spiders (Oxyopes sp. was observed to prey on the insect pests.The biocontrol agent’s one species, lynx spider, Oxyopes sp. population recorded on the crop during Kharif , 2014 ranged from 0.15 to 0.40 /mrl and 0.15 to 0.60/ mrl during Kharif, 2015.

Linear Peptides-A Combinatorial Innovation in the Venom of Some Modern Spiders.

In the venom of spiders, linear peptides (LPs), also called cytolytical or antimicrobial peptides, represent a largely neglected group of mostly membrane active substances that contribute in some spider species considerably to the killing power of spider venom. By next-generation sequencing venom gland transcriptome analysis, we investigated 48 spider species from 23 spider families and detected LPs in 20 species, belonging to five spider families (Ctenidae, Lycosidae, Oxyopidae, Pisauridae, and Zodariidae). The structural diversity is extraordinary high in some species: the lynx spider Oxyopes heterophthalmus contains 62 and the lycosid Pardosa palustris 60 different LPs. In total, we identified 524 linear peptide structures and some of them are in lycosids identical on amino acid level. LPs are mainly encoded in complex precursor structures in which, after the signal peptide and propeptide, 13 or more LPs (Hogna radiata) are connected by linkers. Besides Cupiennius species, also in Oxyopidae, posttranslational modifications of some precursor structures result in the formation of two-chain peptides. It is obvious that complex precursor structures represent a very suitable and fast method to produce a high number and a high diversity of bioactive LPs as economically as possible. At least in Lycosidae, Oxyopidae, and in the genus Cupiennius, LPs reach very high Transcripts Per Kilobase Million values, indicating functional importance within the envenomation process.

Predation potential of hunting and web-building spiders on rice pests of Indian subcontinent

The present study investigated the predation attributes of hunting and web-building spiders of Indian subcontinent against rice-pests, under in-vitro conditions. Field observations revealed that the lynx spider, Oxyopes javanus and the ground-dwelling wolf-spider, Pardosa sumatrana were the most abundant arboreal hunting spiders, while Neoscona theisi and Tetragnatha javana, were the most abundant arboreal web-making spiders, throughout the crop growing season. Laboratory results showed that the prey consumption rates and growth rates of spiders were highest on abundant prey, but the conversion efficiencies were highest on scarce prey. Results identified the highest consumption and growth rates for O. javanus, while conversion efficiencies were highest for N. theisi. The four spider species under study consumed higher number of leafhoppers and lepidopteron adult stage pests in comparison to Leptocorisa bugs and grasshopper nymphs. We, therefore, suggest that the predatory impacts of spiders may be strongly influenced by their species-specific feeding and behavioural attributes, and the anti-predation features of the potential prey.

Mate-searching context of prey influences the predator-prey space race.

Predation risk is a strong driver of prey distribution and movement. However, fitness-influencing behaviours, such as mating, can alter risk and influence predator-prey space-use dynamics. In tree crickets, Oecanthus henryi, mate searching involves acoustic signalling by immobile males and phonotactic movement by females. Space-use patterns in tree crickets relative to their primary predators, green lynx spiders (Peucetia viridans), should therefore depend on their current mate-searching state; whether males are calling or non-calling and whether females are phonotactic or non-phonotactic. We first measured the degree of spatial anchoring of crickets to specific bushes in the field and determined whether that influenced the probability of broad-scale spatial overlap with spiders. In the absence of spiders, all crickets, independent of sex or male calling status, were found to be spatially anchored to specific types of bushes and not uniformly distributed on the landscape. At the broad spatial scale, spiders were more likely to be found on bushes with female crickets and, to a lesser degree, calling male crickets. At a finer spatial scale within a bush, movement strategies of crickets not only varied depending on the presence or absence of a spider, but also on their current mate-searching state. Phonotactic females showed clear predator avoidance, whereas calling and non-calling males moved towards the spider instead of away, similar to predator inspection behaviour seen in many taxa. As the strongly selected sex, males are more likely to undertake risky mate-searching activities, which includes inspection of predator positions. Overall, we found that all crickets were predictably anchored at the landscape scale, but their sex and mate-seeking behaviour influenced the degree of overlap with predators and their antipredator movement strategies. Reproductive strategies within a prey species, therefore, can alter predator-prey space race at multiple spatial scales.

Sex differences in alternative reproductive tactics in response to predation risk in tree crickets

Abstract Alternative reproductive tactics (ARTs) are variable, often discontinuous, behaviours that allow a particular sex to achieve enhanced mating success. Predation risk has been hypothesised to drive the evolution of ARTs, but few empirical studies have examined this. It is unclear whether predators affect fitness of the two sexes directly, by reducing survival, or indirectly, by altering mate searching. In crickets, mate search typically involves acoustic signalling by males and acoustic‐mediated movement towards males by silent females. Males and females may however employ ARTs, which includes silent searching by males, and mating without performing phonotaxis in females. We empirically examined effects of increased predation risk on mate searching behaviour and survival of male and female tree crickets, and their effects on mating success, using field‐enclosure experiments with tree crickets Oecanthus henryi and their primary predator, green lynx spiders Peucetia viridans. Crickets were allocated into three treatments with different levels of predation risk. Increased predation risk strongly reduced survival, and thereby mating success, for both sexes. With increasing predation risk, males reduced calling and increased movement towards neighbouring callers, with negative effects on mating success. By comparing with simulated random movement, we found that male movement was significantly directed towards other calling males, implying a switch to satellite strategies. Female movement behaviour, however, remained unaltered. Males and females thus differed in their response to comparable levels of predation risk, implying that the role of predation as a driver of alternative mate search strategies is sex‐specific. A free Plain Language Summary can be found within the Supporting Information of this article.

Ants Increase Cloverworm Herbivory Via Nonconsumptive Pathways

Generalist arthropod predators often exhibit a range of intraguild interactions reducing their potential efficacy as biological control agents. These interactions may include consumptive or nonconsumptive effects that mediate the impacts of herbivores. We examined interactions among 2 generalist predators, the striped lynx spider (Oxyopes salticus Hentz; Araneae: Oxyopidae) and an ant (Lasius neoniger Emery; Hymenoptera: Formicidae), and a herbivore, the green cloverworm (Hypena scabra F.; Lepidoptera: Erebidae), all prevalent in central Kentucky soybean agroecosystems. We hypothesized that individual predator treatments would reduce green cloverworm survival and resultant leaf damage, but that predators would interfere with each other when both were present. To study these interactions, field cages containing potted soybeans were used to examine 8 treatment combinations (control, cloverworm, spider, ant, spider + cloverworm, ant + cloverworm, ant + spider, and ant + spider + cloverworm). When proportional leaf damage was compared, spider, ant + spider, and spider + cloverworm treatments had significantly less damage than the ant, ant + cloverworm, and ant + spider + cloverworm treatments. Spider presence tended to decrease plant damage while ant presence significantly increased damage. No differences among treatments were found for either spider or cloverworm recovery, indicating potential nonconsumptive effects of ants that may include compensatory feeding. We found that generalist predators, such as L. neoniger, can inhibit biological control due to nonconsumptive interactions even when the same species in a different system provides substantial levels of pest suppression. Resumen Los depredadores de artropodos generalistas a menudo exhiben un rango de interacciones intra-gremial (entre el grupo depredador) reduciendo su eficacia potencial como agentes de control biologico. Estas interacciones pueden incluir efectos consuntivos o no consuntivos que median los impactos de los herbivoros. Examinamos las interacciones entre dos depredadores generalistas, la arana lince rayada (Oxyopes salticus Hentz; Araneae: Oxyopidae) y una hormiga (Lasius neoniger Emery; Hymenoptera: Formicidae), y un herbivoro, el gusano verde de trebol (Hypena scabra F.; Lepidoptera: Erebidae), todos prevalentes en los agroecosistemas de soja del centro del estado de Kentucky. Presumimos que los tratamientos de depredadores individuales reducirian la sobrevivencia del gusano verde de trebol y el dano resultante en las hojas, pero que los depredadores interferirian entre si cuando ambos estuvieran presentes. Para estudiar estas interacciones, se utilizaron jaulas de campo que contenian soja en maceta para examinar 8 combinaciones de tratamiento (el control, el gusano verde de trebol, arana, hormiga, arana + el gusano verde de trebol, hormiga + el gusano verde de trebol, hormiga + arana, y hormiga + arana + el gusano verde de trebol). Cuando se comparo el dano proporcional de las hojas, los tratamientos de arana, hormiga + arana y arana + el gusano verde de trebol tuvieron un dano significativamente menor que los tratamientos de hormiga, hormiga + el gusano verde de trebol y hormiga + arana + el gusano verde de trebol. La presencia de las aranas tiende a disminuir el dano a las plantas, mientras que la presencia de las hormigas aumenta significativamente el dano. No se encontraron diferencias entre los tratamientos para la recuperacion de la arana o el gusano verde de trebol, lo que indica posibles efectos no consuntivos de las hormigas que pueden incluir la alimentacion compensatoria. Descubrimos que los depredadores generalistas, como L. neoniger, pueden inhibir el control biologico debido a interacciones no consumidoras, incluso cuando la misma especie en un sistema diferente proporciona niveles sustanciales de supresion de plagas. Key Words: Hypena scabra; field cage; food web; Lasius neoniger; Oxyopes salticus View this article in BioOne

Striped Lynx Spider Oxyopes salticus (Hentz 1845) (Arachnida: Araneae: Oxyopidae)

The striped lynx spider, Oxyopes salticus (Hentz), is a small, spiny-legged spider and generalist predator that feeds on a wide variety of insect prey, including several economically important insect pests. This lynx spider species is one of the most abundant beneficial spider species in gardens, yards, and agricultural fields throughout North America. https://edis.ifas.ufl.edu/in1259&#x0D; The article is a Featured Creature article on the striped lynx spider, Oxyopes salticus.http://entnemdept.ufl.edu/creatures/MISC/SPIDERS/striped_lynx.html

Comparative Study of Two Synthetic Insecticides Spiromesifen and Thiamethoxam to Determine their Acute and Residual Toxicity against Lynx Spider (Oxyopes javanus)

Comparative Study of Two Synthetic Insecticides Spiromesifen and Thiamethoxam to Determine their Acute and Residual Toxicity against Lynx Spider (Oxyopes javanus)

Field efficacy of some new insecticides against brinjal shoot and fruit borer, Leucinodes orbonalis (Guen.) (Lepidoptera: Pyralidae) and their toxic effects on natural enemies

Brinjal is susceptible to attack of various insect pests from seedling to fruiting stage. Among these, brinjal shoot and fruit borer, Leucinodes orbonalis (Guen.) is the most destructive pest and is considered to be the limiting factor in quantitative as well asqualitative harvest of brinjal fruits. In the present study, efficacy of some new insecticides viz. Pine 6 WG (Emamectin benzoate + Abamectin), Heron 5 EC (Lufenuron), Belt 24 WG (Flubendiamide) and Cyclone 2.5 EC (Lambda-cyhalothrin) were evaluated against brinjal shoot and fruit borer (BSFB) in field condition from the period of October, 2015 to April, 2016. The experiment was laid out in a Randomized Complete Block Design (RCBD) having three replications and two concentrations of each of the insecticides. A total of three spraying was given and finally a cumulative mean was found out. Data were collected on percent shoot infestation, percent fruit infestation, marketable fruit yield (t/ha) and abundances of natural enemies per plant. Results clearly showed that all the insecticides significantly reduced BSFB infestation as well as increased marketable fruit yield compared to the untreated control. The highest shoot (27.40%) and fruit (55.93%) infestation were recorded from control plots. On the other hand, the lowest shoot (6.71%) and fruit (11.58%) infestation were recorded from Pine 6 WG treated plots @ 0.50 g/L that was followed by Heron 5 EC @ 1.0 ml/L (6.89% shoot; 14.51% fruits), Cyclone 2.5 EC @ 1.5 ml/L (15.73% shoot and 16.45% fruits) and Belt 24 WG @ 0.50 g/L (9.53% shoot and 25.47% fruits), respectively. Similar trend was found in case of marketable fruit yield as well. Pine 6 WG and Heron 5 EC were found to be comparatively safe for both ladybird beetle and lynx spiders as their abundances were not changed significantly compared to untreated control. In contrast, the application of Belt 24 WG and Cyclone 2.5 EC has reduced 50 to 60% of the ladybird beetle and lynx spiders populations in brinjal eco-system. The results suggested that two biopesticides viz., Pine 6 WG and Heron 5 EC can be used successfully against BSFB considering minimum shoot and fruit infestation, higher fruit yield and less toxicity to natural enemies in brinjal eco-system.&#x0D; J Bangladesh Agril Univ 17(3): 319–324, 2019