نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه گیاهپزشکی، دانشکده کشاورزی، دانشگاه تهران، کرج،ایران
2 گروه گیاهپزشکی، دانشکده کشاورزی، دانشگاه تهران، کرج، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
In this study, we investigated the effect of familiarity on foraging behaviour of the predatory mites, Amblyseius swirskii and Neoseiulus californicus. The Predators were reared on the bean plants infested with two spotted spider mites. First the predators passed the same aging process. Each group was contained from 3 trios included two protonymps and a larva, colored to be easily recognized. Analysis were performed through F test in SPSS 25. grouping behaviour was tested. The results showed a significant difference between the paired distances (familiar protonymph, protonymph), (unfamiliar protonymph, protonymph), (familiar protonymph, larva), (unfamiliar protonymph, larva) and (unfamiliar larva, larva) in the 5th, 35th and 120th minutes of experiment. The paired distances of protonymphs and larvae were compared at the 5th, 35th and 120th minutes of experiment and we found an increase for the familiar protonymphs which was the least at the 120th minute. The same trend was observed for the unfamiliar protonymphs. Comparing the paired unfamiliar nymphs, we found that the interidividual distances were decreased at the 120th comparing with that at the 5th minutes of experiment. Comparing the paired protonymph and larvae distances in either familiar or unfamiliar patterns, we found the individual distances decreased in a slowly manner in the latter one till the 120th minute of the experiment. The paired distances of unfamiliar larvae showed no significant difference even when the data was compared between the 5th and 120 th minutes of experiment. Comparing the mean length of dorsal shield, we found a significant bigger shield in familiar A. swirskii rather that the unfamiliar ones.
کلیدواژهها [English]
Extended Abstract
Introduction
Familiarity is a key factor shaping social interactions and ecological behaviors in many animal taxa, influencing energy allocation, predator avoidance, and foraging efficiency. In arthropods, particularly predatory mites, the role of familiarity in intragroup behavior and foraging success has been relatively underexplored compared with that in vertebrates. Members of the family Phytoseiidae are among the most important biological control agents against phytophagous mites, including Tetranychus urticae. Their efficiency is not only determined by prey availability but also by behavioral and social interactions within conspecific groups. Previous research has shown that familiar individuals in certain predatory mite species tend to aggregate more closely, forage more efficiently, and exhibit stronger anti-predator responses than unfamiliar individuals. However, evidence regarding the effect of familiarity on developmental performance, grouping tendencies, and predation efficiency in Amblyseius swirskii and Neoseiulus californicus remains scarce. These two species, which differ in feeding behavior, habitat preference, and ecological adaptability, are widely used in integrated pest management (IPM) programs. Accordingly, this study aimed to evaluate the impact of social familiarity on intragroup spacing, developmental traits, and predation performance of these two predatory mite species under controlled laboratory conditions.
Materials and Methods
Colonies of A. swirskii and N. californicus were maintained on bean (Phaseolus vulgaris) leaves infested with T. urticae. Predatory mites were reared in controlled laboratory conditions using detached-leaf arenas following the Overmeer (1985) method, and familiar/unfamiliar groups were generated by allowing synchronous oviposition and early physical contact (familiarity) or by rearing larvae separately (unfamiliarity). Two main experiments were conducted. (1) Intragroup association test: Trios consisting of two protonymphs and one larva were created for each treatment (familiar or unfamiliar), and pairwise interindividual distances were recorded at 5, 35, and 120 minutes after placement in the experimental arenas. Individuals were color-marked for accurate identification. Data were analyzed using one-way ANOVA followed by Tukey’s HSD test to determine significant differences among treatments. (2) Foraging and developmental test: Larvae were reared in familiar or unfamiliar groups and monitored throughout development. Distances between individuals and between shed exuviae were measured using digital micrographs analyzed with DinoCapture software. Predation was quantified as the total number of T. urticae eggs consumed until adulthood. The dorsal shield length was measured under a light microscope as a proxy for body size. Each treatment included 20 replicates per species and familiarity condition, and data were analyzed using independent-sample t-tests and ANOVA.
Results and Discussion
The results demonstrated a consistent and significant effect of familiarity on spatial association, developmental spacing, and foraging efficiency in both predatory mite species. In N. californicus, protonymphs from familiar groups exhibited significantly shorter interindividual distances, particularly after 120 minutes of observation, indicating a gradual tendency toward aggregation among familiar individuals. This pattern supports earlier findings in P. persimilis. In contrast, distances among unfamiliar larvae remained nearly constant, reflecting their limited mobility and lower exploratory activity. Comparisons across developmental stages revealed that familiar protonymphs and deutonymphs consistently maintained shorter distances than unfamiliar ones, suggesting that early-life social exposure promotes lasting cohesion within conspecific groups. Distances between shed exuviae followed similar trends, reinforcing the idea that familiarity influences not only behavioral interactions but also developmental spatial patterns. Predation assays further confirmed the positive role of familiarity: both A. swirskii and N. californicus consumed significantly more eggs of T. urticae when reared in familiar groups compared with unfamiliar ones. These findings align with the “Limited Attention Theory,” which suggests that individuals in familiar groups allocate less energy to monitoring conspecifics and more to essential activities such as foraging and reproduction. Interestingly, A. swirskii showed a significant increase in dorsal shield length under familiar conditions, while no such difference was observed in N. californicus. This may indicate species-specific physiological plasticity, possibly related to setal (hair) length and adaptation to webbed prey environments. Our findings corroborate previous studies showing that familiarity reduces aggressive interactions and enhances cooperative foraging efficiency. Strodl and Schausberger (2012, 2013) reported that familiar P. persimilis individuals formed tighter aggregations and exhibited enhanced predatory performance. Similarly, Griffiths et al. (2004) observed in salmonids that familiar groups responded faster to external threats and achieved higher feeding efficiency compared to unfamiliar ones. The present study extends these observations to A. swirskii and N. californicus, providing new evidence that familiarity enhances the biocontrol potential of predatory mites. Importantly, the effect of familiarity differed between species. In A. swirskii, larger dorsal shield size may confer a mechanical advantage for penetrating T. urticae webs and improving prey access, whereas in N. californicus, enhanced aggregation behavior appeared to be the dominant factor improving foraging success. These interspecific differences underscore that familiarity affects multiple behavioral and physiological traits, whose outcomes depend on species-specific ecology and adaptation.
Conclusion
The present study demonstrates that social familiarity significantly influences grouping behavior, developmental interactions, and predation efficiency in A. swirskii and N. californicus. Familiar individuals aggregated more closely, consumed more prey, and in the case of A. swirskii, developed larger body sizes. These findings underscore the ecological and applied importance of social familiarity in shaping predator performance and suggest that promoting familiar cohorts during mass-rearing could enhance the efficiency of these predatory mites in biological control programs. Further research should investigate the long-term effects of familiarity on reproductive success, dispersal, and field-level efficacy under variable environmental conditions.
Keywords: Predatory mite; Familiarity; Foraging behavior; Phytoseiidae; Behavioral ecology
“Conceptualization, Azadeh Zahedi Golpayegani and Alireza Saboori ; methodology, Parisa Jalili Zonouzi.; software, Azadeh Zahedi Golpayegani.; validation, Azadeh Zahedi Golpayegani and Alireza Saboori .,formal analysis, Azadeh Zahedi Golpayegani.; investigation, Parisa Jalili Zonouzi, Helen Mohammadi and Navid Sehat Niaki.; resources, Azadeh Zahedi Golpayegani.; data curation, Navid Sehat Niaki and Azadeh Zahedi Golpayegani.; writing—original draft preparation, Azadeh Zahedi Golpayegani and Navid Sehat Niaki.; writing—review and editing, Navid Sehat Niaki.; supervision, Azadeh Zahedi Golpayegani.; project administration, Azadeh Zahedi Golpayegani.; funding acquisition, University of Tehran. All authors have read and agreed to the published version of the manuscript.”
All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
Not applicable.
The authors would like to thank University of Tehran for preparing the fund of research and also all participants of the present study.
The study was approved by the Ethics Committee of the University of Tehran. The authors avoided data fabrication, falsification, plagiarism, and misconduct.
Acarology, Mite Ecology and Behaviour
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