Vocal mimicry of the paraside whydahs (Vidua) and response of female whydahs to the songs of their hosts (Pytilia) and their mimics

Parasitic paradise whydahs (Vidua paradisaea) mimic the vocalizations of their hosts, Pytilia melba. Photostimulated female whydahs isolated in large aviaries responded to broadcasts of recorded song. Approach occurred significantly more often to songs of the host species P. melba than to the similar P. phoenicoptera. Females approached with equal frequency the songs recorded from their hosts and the mimetic songs of the male whydahs. No significant differences were found between the responses of females to songs of sympatric and allopatric forms of their host. It is suggested that mimetic songs of males and the responses of females are behavioural isolating mechanisms among species of whydahs.     

Colonization of host patches following long-distance dispersal by a goldenrod beetle, Trirhabda virgata

1. The arrival of the chrysomelid beetle Trirhabda virgata on isolated patches of its host Solidago altissima was closely monitored to determine how conspecific density and host condition influence colonization.
2. Experimental host patches, which were set on the roof of a four-storey building located 0.7 km from the nearest naturally occurring hosts, were frequently colonized by beetles over a 2-week dispersal period.
3. Females preferred lush host patches that were free from simulated Trirhabda chewing damage. Females colonized lush patches more often than defoliated patches at two spatial scales, when patches were 2 m and 25 m apart. Males did not show a strong preference for lush plants.
4. Males aggregated on plants that already contained adult conspecifics, apparently increasing their reproductive success. Females did not respond to the presence of adults on the patch.
5. Ninety-five per cent of the females arriving on the isolated plants had mated before flying, indicating that lone females are able to colonize empty stands.
6. By avoiding heavily defoliated plants, females should dissipate local outbreaks and spread their offspring away from over-exploited areas.     

Host-use pattern of the shrimp <Emphasis Type="Italic">Periclimenes paivai</Emphasis> on the scyphozoan jellyfish <Emphasis Type="Italic">Lychnorhiza lucerna</Emphasis>: probing for territoriality and inferring its mating system

In symbiotic crustaceans, host-use patterns vary broadly. Some species inhabit host individuals solitarily, other species live in heterosexual pairs, and even other species live in aggregations. This disparity in host-use patterns coupled with considerable differences in host ecology provide opportunities to explore how environmental conditions affect animal behavior. In this study, we explored whether or not symbiotic crustaceans inhabiting relatively large and structurally complex host species live in aggregations. We expected Periclimenes paivai, a small caridean shrimp that lives among the tentacles of the large and morphologically complex scyphozoan jellyfish Lychnorhiza lucerna, to live in groups given that the host traits above constraint host-monopolization behaviors by symbiotic crustaceans. We described the population distribution of P. paivai during a bloom of L. lucerna near the mouth of the Paraíba River estuary in Paraíba, Brazil. The population distribution of P. paivai did not differ statistically from a random Poisson distribution. Male shrimps were most often found dwelling on the surface of L. lucerna individuals as small groups (2–4 individuals), in agreement with expectations. Periclimenes paivai is a sexually dimorphic species with males attaining smaller average body sizes than females and exhibiting no elaborated weaponry (claws). Females, but not males, experience positive allometry in cheliped size and were found living solitarily in small but not large host individuals. The above suggest that females might be territorial or that they might be competing for resources (i.e., food) likely expected to impact their reproductive output. Our results agree, but only partially, with the idea that large and morphologically complex host species should harbor non-territorial gregarious symbiotic crustaceans. Symbiotic crustaceans represent excellent models to improve our understanding about the conditions driving the social behavior of marine organisms.     

Sex‐biased oviposition by a nursery pollinator on a gynodioecious host plant: Implications for breeding system evolution and evolution of mutualism

Dioecy, a breeding system where individual plants are exclusively male or female, has evolved repeatedly. Extensive theory describes when dioecy should arise from hermaphroditism, frequently through gynodioecy, where females and hermaphrodites coexist, and when gynodioecy should be stable. Both pollinators and herbivores often prefer the pollen‐bearing sex, with sex‐specific fitness effects that can affect breeding system evolution. Nursery pollination, where adult insects pollinate flowers but their larvae feed on plant reproductive tissues, is a model for understanding mutualism evolution but could also yield insights into plant breeding system evolution. We studied a recently established nursery pollination interaction between native Hadena ectypa moths and introduced gynodioecious Silene vulgaris plants in North America to assess whether oviposition was biased toward females or hermaphrodites, which traits were associated with oviposition, and the effect of oviposition on host plant fitness. Oviposition was hermaphrodite‐biased and associated with deeper flowers and more stems. Sexual dimorphism in flower depth, a trait also associated with oviposition on the native host plant (Silene stellata), explained the hermaphrodite bias. Egg‐receiving plants experienced more fruit predation than plants that received no eggs, but relatively few fruits were lost, and egg receipt did not significantly alter total fruit production at the plant level. Oviposition did not enhance pollination; egg‐receiving flowers usually failed to expand and produce seeds. Together, our results suggest that H. ectypa oviposition does not exert a large fitness cost on host plants, sex‐biased interactions can emerge from preferences developed on a hermaphroditic host species, and new nursery pollination interactions can arise as negative or neutral rather than as mutualistic for the plant.     

Female cowbirds have more accurate spatial memory than males

Brown-headed cowbirds (Molothrus ater) are obligate brood parasites. Only females search for host nests and they find host nests one or more days before placing eggs in them. Past work has shown that females have a larger hippocampus than males, but sex differences in spatial cognition have not been extensively investigated. We tested cowbirds for sex and seasonal differences in spatial memory on a foraging task with an ecologically relevant retention interval. Birds were trained to find one rewarded location among 25 after 24 h. Females made significantly fewer errors than males and took more direct paths to the rewarded location than males. Females and males showed similar search times, indicating there was no sex difference in motivation. This sex difference in spatial cognition is the reverse of that observed in some polygynous mammals and is consistent with the hypothesis that spatial cognition is adaptively specialized in this brood-parasitic species.     

Mate selection in the fly Scatophaga stercoraria: female choice in a male-controlled system

Sexual pairing in the fly Scatophaga stercoraria involves ‘capture’ of females by males. Sizerelated choice by males and females is considered, because these flies are highly variable in size, and size strongly affects reproductive success. Results show that males do not discriminate among females on the basis of size. Females choose large males when free to select mates. They move toward larger males when contronted by more than one possible mate, and their movement on the oviposition site takes them to areas where large males are more common. Females paired with large males gain from (1) reduced harm in struggles; (2) more rapid copulation and oviposition, with lower risk to the female and her progeny; and (3) greater ability to escape danger during copulation. These benefits may account for female preference for large males.     

Kin recognition by the predatory mite Iphiseius degenerans: discrimination among own, conspecific, and heterospecific eggs

1. Kin recognition is important in many social insects, but has also been found in several nonsocial insects such as parasitoids, where it plays an important role in oviposition behaviour. In nonparasitic arthropods, however, the fitness of ovipositing females also depends on the oviposition behaviour of related and unrelated females, especially when eggs are oviposited in clusters by several females. 2. In this paper, kin recognition in a predatory mite, Iphiseius degenerans, is studied. Mothers are capable of determining offspring sex ratio, and cannibalism on juvenile stages is a common phenomenon. Therefore, kin recognition is expected to occur in this predator. 3. Oviposition behaviour of this species is particularly interesting because it alternates foraging bouts in flowers with deposition of a single egg at a time on a leaf, where predation risk is lower. The eggs are not scattered but are deposited in clusters. After feeding in a flower, females therefore have to locate clusters of eggs. 4. Experiments on two‐choice arenas showed that females prefer to oviposit close to conspecific eggs rather than close to heterospecific eggs. Females also showed a preference for ovipositing near closely related conspecific eggs rather than more distantly related eggs. 5. Females tended to displace eggs of heterospecifics more frequently than eggs of conspecifics. 6. These behavioural observations show that females can discriminate not only between conspecific and heterospecific eggs but also between eggs that vary in degree of relatedness. This enables females to oviposit in clusters containing related eggs and thus avoid cannibalism by non‐kin and/or produce adaptive sex ratios despite the fact that the adults commute between flowers and leaves.     

Host selection by the autoparasitoid Encarsia pergandiella on primary (Bemisia tabaci) and secondary (Eretmocerus mundus) hosts

In autoparasitoids, females are generally primary endoparasitoids of Hemiptera, while males are hyperparasitoids developing in or on conspecific females or other primary parasitoids. Female‐host acceptance can be influenced by extrinsic and/or intrinsic factors. In this paper, we are concerned with intrinsic factors such as nutritional status, mating status, etc. We observed the behavior of Encarsia pergandiella Howard (Hymenoptera: Aphelinidae) females when parasitizing primary (3rd instar larvae of Bemisia tabaci Gennadius [Homoptera: Aleyrodidae]) and secondary hosts (3rd instar larvae and pupae of Eretmocerus mundus Mercet [Hymenoptera: Aphelinidae]) for a period of 1 h. Females had different reproductive (virgin or mated younger) and physiological (fed elder or mated elder) status. Virgin females killed a large number of secondary hosts while investing a long time per host. However, they did not feed upon them. Mated females killed a lower number of secondary hosts and host feeding was observed in both consuming primary and secondary hosts. It was common to observe host examining females of all physiological statues tested repeatedly stinging the same hosts when parasitizing, killing or rejecting them. Fed elder females parasitized more B. tabaci larvae than E. mundus larvae or pupae, while investing less time on the primary host than on the secondary host. They also parasitized more B. tabaci larvae than mated elder females, while investing less time per host. The access of females to honey allowed them to lay more eggs.     

Males,but not females,perform strategic mate searching movements between host plants in a leaf beetle with scramble competition polygyny

Mate searching is assumed to be performed mostly by males, but when females benefit from multiple mating or are under risk of failing to mate, they may also perform mate searching. This is especially important in scramble competition polygynies, in which mate searching is the main mechanism of mate competition. Typically, more mobile individuals are expected to achieve higher mating success because mobility increases their probability of finding mates. If we assume individual movements are mainly explained by mate searching in scramble competition polygynies, we can investigate searching strategies by asking when individuals should leave their location and where they should go. We hypothesize that individuals will leave their locations when mating opportunities are scarce and will seek spatially close sites with better mating opportunities. We tested these hypotheses for males and females of Leptinotarsa undecimlineata, a leaf beetle with scramble competition polygyny in which both sexes are promiscuous. Individuals mate and feed exclusively on Solanum plants, and thus, individual movements can be described as switches between plants. Females were less likely than males to leave isolated plants, and both males and females moved preferentially to neighboring plants. Males were more likely to leave when the local number of females was low, and the number of males was high. They moved to plants with more females, a behavior consistent with a mate searching strategy. Females were more likely to move to plants with fewer males and many females, a behavior consistent with male harassment avoidance. Strategic movement is widely considered in foraging context, but seldom in a mate searching context. Considering that selection to minimize searching costs, maximize mating success, and minimize harassment may be ubiquitous in nature, we argue that strategic movements by mate searching individuals are likely to occur in many species.     

Performance of the Striped Mealybug Ferrisia virgata Cockerell (Hemiptera: Pseudococcidae) under Variable Conditions of Temperature and Mating

Mealybugs have strong associations with their host plants due to their limitations for dispersal. Thus, environmental conditions and host quality may impact the biological traits of mealybugs. To the best of our knowledge, we are the first to report on the biology of a Brazilian population of the striped mealybug Ferrisia virgata Cockerell (Hemiptera: Pseudococcidae), which has recently been reported to infest cotton in Brazil. We evaluated the development and reproductive performance of F. virgata reared under different temperatures (25, 27, and 28°C) and mating status. The type of reproduction was also studied with insects reared on a factitious host and on cotton plants. Shorter development was obtained at 28°C as follows: nymphs generating males and females exhibited three and four instars with a mean duration of 19.1 and 20.5 days, respectively. The nymphal viability ranged from 77 to 96%, and was highest at 25°C. Females reared at 28°C initiated reproduction earlier (16.4 days), but the reproductive period was similar in all temperatures (～16.2 days). Females produced more nymphs at 27 and 28°C (440 and 292 neonates) than at 25°C (277 neonates), although they lived longer at 25°C (63 days). Ferrisia virgata females exhibited only sexual reproduction. Thus, only mated females produced offspring, whereas unmated females died without reproducing. Therefore, the studied population of F. virgata exhibited only sexual reproduction with high survival and offspring production when fed cotton. Furthermore, pumpkin is a feasible host for mass rearing this mealybug species in the laboratory, an opening avenue for future studies.     

Adaptation to a novel host modifies host discrimination by the seed beetle Callosobruchus maculatus

Females of the seed beetle Callosobruchus maculatus avoid adding eggs to seeds that already bear eggs. Geographical variation in this behaviour has been thought to depend on differences in host size. In populations that attack small-seeded legumes, only one or two larvae can develop within a seed, and females are especially adept at detecting and rejecting occupied (egg-laden) seeds. We performed a mass-selection experiment in which replicate lines of a population associated with a small host (mung bean, Vigna radiata) were either maintained on this host or were transferred to a larger host (cowpea, Vigna unguiculata) that can support several larvae per seed. After more than 40 generations, we estimated the strength of host discrimination by presenting females a choice of egg-free and egg-laden seeds, and by quantifying how uniformly females spread their eggs among egg-free seeds. Compared to females maintained on mung bean, females from cowpea lines were more likely to accept occupied seeds in choice tests. They also distributed their eggs less uniformly, especially when cowpea served as the test host. Cowpea lines thus evolved to resemble populations that have long been associated with the larger host. A separate study showed that weaker host discrimination in the cowpea lines was accompanied by a decline in larval competitiveness, which may have further relaxed selection for avoidance of occupied hosts. Our results demonstrate that switching to a novel resource can produce rapid and predictable changes in a fitness-related insect behaviour. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour     

The role of female search behaviour in determining host plant range in plant feeding insects: a test of the information processing hypothesis

Recent theoretical studies have suggested that host range in herbivorous insects may be more restricted by constraints on information processing on the ovipositing females than by trade-offs in larval feeding efficiency. We have investigated if females from polyphagous species have to pay for their ability to localize and evaluate plants from different species with a lower ability to discriminate between conspecific host plants with differences in quality. Females of the monophagous butterflies Polygonia satyrus, Vanessa indica and Inachis io and the polyphagous P. c-album and Cynthia cardui (all in Lepidoptera, Nymphalidae) were given a simultaneous choice of stinging nettles (Urtica dioica) of different quality. In addition, the same choice trial was given to females from two populations of P. c-album with different degrees of specificity. As predicted from the information processing hypothesis, all specialists discriminated significantly against the bad quality nettle, whereas the generalists laid an equal amount of eggs on both types of nettle. There were no corresponding differences between specialist and generalist larvae in their ability to utilize poor quality leaves. Our study therefore suggests that female host-searching behaviour plays an important role in determining host plant range.     

Foraging behavior of a Dipteran leaf miner on exploited and unexploited hosts

Summary The foraging behavior of females of the leaf miner, Agromyza frontella (Rondani), (Diptera: Agromyzidae) when encountering unexploited or exploited alfalfa plants was studied in large field cages and in laboratory bioassays. Females did not recognize any exploited leaflets before contacting them and did not distinguish between leaflets with an egg or first instar larva and unexploited leaflets, even after contact. Only one fly oviposited in leaflets which contained 80–120 nutrition holes, one late second or third instar larva or which were marked with an epideictic pheromone in field cages. In laboratory bioassays females oviposited less in leaflets containing a second or third instar larva or an empty larval mine than in unexploited ones. Females foraging on unexploited leaflets engaged in area-restricted search and 10 of 11 females remained on the test plant for the full 60 min of observation. However, females foraging on exploited plants were much more active, spent a greater proportion of their time searching for suitable hosts, had the highest rates of visitation to all above ground plant parts and emigrated to the cage walls before 60 min had elapsed. These quantitative measures of foraging behavior indicated that females ranked plants after landing on them in the following order: unexploited plants >plants marked with pheromone or with many nutrition holes >plants with late instar larvae. The order of host ranking by foragers was in general agreement with the suitability of the host plants for larval survival, development and reproduction, as estimated from previous laboratory studies.Females of A. frontella foraging on unexploited alfalfa plants fed and oviposited significantly more often in the upper apical leaflets than in the lower, older leaflets. However, the choice of feeding site by flies on exploited plants did not vary with leaflet position (age), indicating that females fed in order to sample leaflet quality and that females investigated lower (older) leaves after they discovered that the preferred upper leaves were occupied. These data suggest that high quality oviposition sites may be limiting for A. frontella females, which could explain why superparasitism of leaflets sometimes occurs in nature, even when unexploited sites are available.     

Tomato variety affects larval survival but not female preference of the generalist moth Trichoplusia ni

In herbivorous insects, the choice that females make for a suitable host plant is crucial for survival of its offspring because the neonate larvae are generally not capable of moving great distances. The preference-performance hypothesis states that herbivore females will choose to oviposit on hosts on which their offspring will have better performance. In this study, we investigated whether Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) females are able to discriminate among a weedy race, a landrace, and a commercial cultivar of tomato plants, Solanum lycopersicum L. (Solanaceae), and how their choice affects the offspring performance. Additionally, we identified the volatile compounds and recorded the density of glandular trichomes of the tomato plants. Females did not show a preference for any of the three types of tomato plants. Females oviposited more on the adaxial surface of leaves of commercial cultivar plants than on (any surface of) leaves of weedy-race plants. The relative abundance of volatiles varied quantitatively among the three types of tomato plants. Commercial cultivar plants released a higher abundance of volatiles than weedy race and landrace plants. Weedy-race plants had a higher density of glandular trichomes types I and VI than the commercial cultivar. More neonate larvae died if fed on the weedy race and landrace plants than when reared on commercial cultivar plants. Results suggested that the higher mortality of T. ni larvae may be related to a higher density of glandular trichomes on landrace and weedy-race plants than on commercial cultivar plants, although other constitutive and induced defenses may be involved. Our results do not support the preference-performance hypothesis.     

Lekking and the small-scale distribution of the sexes in the Caribbean fruit fly,Anastrepha suspensa (Loew)

Male and female Anastrepha suspensa(Loew) had a clumped distribution in the foliage of their guava host plants. Males were no closer to other males than they were to females or than females were to other females. Flies were often found in roughly the same locations over time. However, contemporaries (flies present at the same time) were closer to each other than subsequent flies were to their predecessors. Males were more likely to be found near spots previously occupied by males than they were to spots used previously by females. Some trees had more flies than others, but there was no regional (northwest, etc.) preference within trees. Females were no more likely to be found in the vicinity of clumped (lekking) males than they were by isolated males. About a third of the females taken from inside leks had sperm in their spermathecae, and it is not clear if their motive for being in these areas was sexual. In pairs of males (within 15 cm of each other), the larger fly tends to be in a position farther up the branch, suggesting that larger males may control preferred territories. It seems possible that males attempting to intercept females accumulate in favorable microhabitats where females are likely to be concentrated and that leks have evolved from such clumping.     

Human-induced hybridization among congeneric endemic plants on Tenerife, Canary Islands

Endemic genera on oceanic islands often evolved striking morphological and ecological differences among species, with weak postzygotic reproductive isolation. Human activities can lead to increased connectivity and can thereby promote secondary contact and hybridization between previously isolated species. We studied this phenomenon in three species of the genus Pericallis (Asteraceae) on Tenerife, Canary Islands. A total of 53 populations was sampled, including morphologically uniform as well as mixed populations containing morphologically diverse individuals. All plants were analyzed both genetically using AFLP markers and morphometrically. As expected, morphological analysis clearly separated the plants from the uniform populations in three clusters, with distinguishing characters corresponding to those used in species identification. The three species were also grouped into distinct genetic clusters in a structure analysis, although no private alleles were observed. Adding the mixed population data to the analyses provided evidence for extensive hybridization among species, predominantly between P. cruenta and P. echinata, and between P. cruenta and P. tussilaginis, and morphological and genetic signals were congruent. The mixed populations were geographically located in between the uniform populations and were found in road verges significantly more often than the uniform populations. The observed distribution strongly suggests that hybridization between originally isolated species is recent, promoted by secondary contact due to human disturbance and the construction of roads.     

Body size and fitness relation in male and female Diaeretiella rapae

A strong relationship exists between body size and fitness in parasitoids. However, it is unclear whether the relationship is symmetric or asymmetric in males and females. The present study investigated the body size and fitness relationship in Diaeretiella rapae emerged from small and large nymphs of cabbage aphid Brevicoryne brassicae. A positive relationship existed between the size of the aphid host and growth of parasitoid larva developing in it. The fitness gain in males and females was not proportionate to their body size gain. Females mated with larger males produced 10?% more female offspring than females mated with smaller males. However, females that developed in large hosts produced 62?% more offspring (total male and female) than the females emerged from smaller hosts. The findings suggest that the number of offspring and the progeny sex ratio were affected by the body size of both male and female D. rapae.     

Pushy males and choosy females: courtship disruption and mate choice in the lekking great snipe

We studied the effects of male disruptive behaviour on female mate choice and male mating success in the great snipe, Gallinago media, a lekking bird. Harassment from neighbouring males, a widespread behaviour in lekking animals, was the most prevalent cause of females leaving a male territory. Several lines of evidence show that females did not prefer to mate with males able to protect them from harassment. Males that obtained mating success were no less likely to suffer disruptions and females were no less likely to be disrupted when with their preferred male. Females returned to the male they later mated with, despite being repeatedly chased away by neighbours. The probability that an individual female returned and solicited mating from a male was 15 times higher for the male she was chased away from compared to the neighbour that chased her away. Females returned as often or more to the territory owner after being disrupted, compared to after leaving the territory without being harassed. Our results suggest that female great snipes are extremely choosy, but also that females do not gain direct benefits (harassment avoidance) by mating with certain males. Females appear to have neither direct nor indirect preferences for dominance that could give them such benefits: females appeared choosy despite, not because of, harassment. If females gain indirect benefits (genetically superior offspring) by being choosy, this is also likely to be unrelated to any dominance among males.     

The effects of host race, gender, and host plant distribution on alighting behavior, mating, and oviposition in Eurosta solidaginis

Eurosta solidaginis Fitch (Diptera: Tephritidae) has formed host races on Solidago altissima L. and Solidago gigantea Ait. (Asteraceae), and reproductive isolation between these host races is brought about in part by host‐associated assortative mating. Any non‐assortative mating creates the potential for gene flow between the populations, and we investigated the conditions that favored non‐assortative mating. We hypothesized that the frequency of non‐assortative mating would be influenced by differences in the behaviors of the host races and sexes and by the presence and pattern of distribution of the two host species. To test these hypotheses, we caged flies on four combinations of 32 potted host plants: all S. altissima, all S. gigantea, and cages with both host species arranged in either two pure species blocks or randomly dispersed. We recorded the number of flies of each host race that alighted on each host species and the frequency of mating within and between the host races. Males of both host races were observed on plants more frequently than females. Flies of the host race from S. gigantea (gig flies) were observed on plants in greater absolute numbers, and they mated more frequently than flies of the host race from S. altissima (alt flies). In all treatments, gig flies of both sexes were found on non‐natal host plants significantly more frequently than alt flies, and gig females showed a weaker preference for their host species than did gig males or alt flies of either gender for their respective natal hosts. Assortative mating predominated in all treatments, and flies from each host race mated more frequently in cages containing their own host plant. The frequency of non‐assortative mating varied among treatments, with the matings between alt ♀ × gig ♂ being more common in the pure S. altissima treatment and the gig ♀ × alt ♂ being more frequent in the pure S. gigantea and random treatments. Matings between gig ♂ × alt ♀ were more common overall than the reciprocal mating, because gig males were more active in pursuing matings and in alighting on the non‐natal host plant than alt flies. Non‐assortative matings were more frequent in the random than in the block treatments, but this difference was not significant. Because of strong selection against oviposition into the alternate host, we hypothesized that host plant distribution would not affect oviposition preference. We tested this hypothesis by examining the oviposition behavior of naïve, mated females in two treatments in which both host species were present: either arranged in blocks or randomly dispersed. Females oviposited only into their natal host, regardless of host plant distribution.     

Influence of plant structural complexity on the foraging success of Trichogramma minutum: a comparison of search on artificial and foliage models

The influence of structural complexity on the foraging success for host eggs (Ephestia kuehniella Zeller) by Trichogramma minutum Riley was investigated in the laboratory. Naive females were released into arenas with structurally different paper models or foliage (simple: trembling aspen Populus tremuloides Michx., complex: balsam fir Abies balsamea L.). Observations of individual females were made every 15 min and searching success was measured by the number of host egg clusters found and the amount of time taken to find them, within a period of 196 min. Females found significantly more egg clusters and were quicker at finding them on the sample paper and foliage surfaces than on the most complex paper or foliage surfaces. Older females (2–3 days) were more successful and searched quicker than younger (<24 h) females on all paper surfaces. The timed observations suggested that wasps which spent more time walking had a significantly decreased probability of finding an egg mass and were significantly slower at finding them. Females that spent more time on paper surfaces had an increased probability of finding an egg mass. The significance of searching differences is discussed in relation to the potential effects of plant surfaces on Trichogramma movements and to the physiological readiness of the wasp.