Odour-mediated responses of a predatory mirid bug and its prey, the two-spotted spider mite

It has been shown that many natural enemies of herbivorous arthropods use herbivore induced plant volatiles (HIPVs) to locate their prey. Herbivores can also exploit cues emitted by plants infested with heterospecifics or conspecifics. A study was conducted to test whether green bean HIPVs as well as odours emitted directly by spider mites influenced the orientation behaviour of the predatory mirid bug, Macrolophus caliginosus and its prey, Tetranychus urticae in a Y-tube olfactometer. Our results show that both spider mites and M. caliginosus preferred spider mite infested green bean plants to uninfested plants. For M. caliginosus this response was mediated by HIPVs whereas for T. urticae it was mediated through a composite response to both HIPVs and odours emitted directly by the conspecifics (and their associated products). The results may be of use in practical biocontrol situations, through e.g., plant breeding for improved HIPV production, conditioning of mass-reared predators to appropriate cues, and employment of “push–pull-strategies” by using HIPVs.     

Induced defence in detached uninfested plant leaves: effects on behaviour of herbivores and their predators

Summary Induction of plant defence against herbivores may include the attraction by volatile infochemicals of natural enemies of the herbivore. The emitted volatiles that mediate this attraction may also affect the behaviour of the herbivore itself. In this paper we investigate the response of the herbivorous spider miteTetranychus urticae and the predatory mitePhytoseiulus persimilis towards volatiles whose production is induced in detached Lima bean leaves. Detached uninfested Lima bean leaves were incubated on wet cotton wool on which bean leaves infested with spider mites (T. urticae) were present simultaneously or had been present previously. These treatments induce the production of volatile infochemicals in the uninfested bean leaf tissue: predatory mites are attracted and spider mites are deterred. These are the first data on the response of predators and herbivores to plant volatiles whose production was induced in detached uninfested leaves.     

Do anthocorid predators respond to synomones from Psylla-infested pear trees under field conditions?

Because Y-tube olfactometer experiments in the laboratory showed a response of anthocorid bugs to odour fromPsylla-infested leaves, it was of interest to assess its relevance under field circumstances. This was done by measuring the density of predatory bugs on pear trees adjacent toPsylla-infested or control trees that were covered with fine mesh gauze-screens. In this way odours from these caged trees could spread through the screen, while contact with thePsylla prey in the cage was prevented. The density of anthocorid predators around cages with heavily infested trees was significantly higher than around uncaged control trees and around cages containing uninfested or little infested trees. Covering a cage withPsylla-infested trees by an airtight plastic sheet led to an immediate drop in the density of anthocorid predators, whereas removal of the sheet led to predator aggregation again. The results of these field experiments strongly support the hypothesis that anthocorid predators respond to volatile chemicals emanating fromPsylla-infested pear trees.     

Parasitoids follow herbivorous insects to a novel host plant,generalist predators less so

The ‘enemy‐free space’ hypothesis predicts that herbivorous insects can escape their natural enemies by switching to a novel host plant, with consequences for the evolution of host plant specialisation. However, if natural enemies follow herbivores to their novel host plants, enemy‐free space may only be temporary. We tested this by studying the colonisation of the introduced tree Eucalyptus grandis (Hill) Maiden (Myrtaceae) by insects in Brazil, where various species of herbivores have added eucalyptus to their host plant range, which consists of native myrtaceous species such as guava. Some herbivores, for example, Thyrinteina leucoceraea Ringe (Lepidoptera: Geometridae), cause outbreaks in eucalyptus plantations but not on guava, possibly because eucalyptus offers enemy‐free space. We sampled herbivores (mainly Lepidoptera species) and natural enemies on eucalyptus and guava and assessed parasitism of Lepidoptera larvae on both host plant species during ca. 2 years. Overall, predators were encountered more frequently on guava than on eucalyptus. In contrast, parasitoids were encountered equally and parasitism rates of Lepidoptera larvae were similar on both host plants. This indicates that herbivores may escape some enemies by moving to a novel host plant. However, this escape may be temporary and may vary with time. We argue that studying temporal and spatial patterns of enemy‐free space and the response of natural enemies to host use changes of their herbivorous prey is essential for understanding the role of natural enemies in the evolution of host plant use by herbivorous arthropods.     

Predator responses to novel haemolymph defences of western corn rootworm (Diabrotica virgifera) larvae

Many herbivorous arthropods use defensive chemistry to discourage predators from attacking. This chemistry relies on the ability of predators to rapidly learn to recognize and avoid offensive stimuli. Western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), employs multifaceted chemical defences in its haemolymph, which may contribute significantly to its success as a major economic pest. Here, we test the hypothesis that agrobiont predators can rapidly learn to recognize and avoid WCR larvae, and will thereby reduce their contribution to WCR suppression. In controlled feeding assays, the effectiveness of WCR haemolymph defences varied across three predator taxa (crickets, centipedes, and ants). Centipedes (Chilopoda: Lithobiidae) were minimally affected by WCR defences, but crickets [Gryllus pennsylvanicus Burmeister (Orthoptera: Gryllidae)] spent less time feeding on WCR than on an undefended control prey, house fly maggots. However, we uncovered no evidence indicating that experienced crickets rapidly learn to avoid WCR larvae, indicating that haemolymph defences offer few, if any, survival benefits for WCR. Colonies of ants [Lasius neoniger Emery (Hymenoptera: Formicidae)] switched from low worker participation in initial attacks on WCR to higher worker participation in subsequent attacks, indicating an attempt to overcome, rather than avoid, WCR haemolymph defences. These results suggest that a diverse assemblage of natural enemies will show a diverse array of behavioural responses to toxic pest prey, and highlight the importance of behavioural diversity in driving the function of natural enemy assemblages.     

Leaf beetle larvae,Plagiodera versicolora (Coleoptera: Chrysomelidae), show decreased performance on uninfested host plants exposed to airborne factors from plants infested by conspecific larvae

Undamaged plants are known to suffer less damage from herbivores when previously exposed to airborne factors from neighboring plants that are either infested or artificially damaged. However, to date, the effects of such a defensive phenomenon on performance of herbivorous insects have not been clearly shown. Here, we studied such effects in an interaction between a willow plant, Salix eriocarpa Franchet et Savatier (Salicales: Salicaceae), and a specialist leaf beetle, Plagiodera versicolora (Laicharting) (Coleoptera: Chrysomelidae). In a wind tunnel, uninfested willow plants were placed downwind of willow plants infested by leaf beetle larvae for 4 days. As a control, we placed uninfested plants downwind of uninfested plants in the tunnel. After exposure, downwind plants were served to leaf beetle larvae. Pupal weight, larval survival rates, and the leaf area consumed by larvae all decreased significantly, and larval developmental duration increased significantly, when larvae fed on willow plants downwind of infested plants were compared with those downwind of uninfested plants. These results showed that airborne factors from infested willow plants negatively affected the performance of leaf beetle larvae. Further studies are needed to identify the active factor(s) from the infested willow plants affecting the performance of leaf beetle larvae.     

Role of volatile infochemicals in foraging behavior of the leafminer parasitoidDacnusa sibirica (Diptera: Agromyzidae)

Previous investigations suggested that the leafminer parasitoid Dacnusa sibirica Telenga does not use a volatile hostrelated infochemical in foraging for hosts. Parasitoids landed with equal frequencies on an uninfested tomato plant and on a tomato plant infested with larvae of the leafminer Liriomyza bryoniae (Kalt.) (Hendrikse et al., 1980). In contrast, we found that volatile infochemicals emitted by uninfested and leafminer-infested tomato plants differently affected the parasitoid 's foraging behavior in a windtunnel. This was obvious from the proportion of wasps flying upwind but not from the proportion of wasps landing on the leaves. Latency time on an uninfested tomato leaflet and proportion of latency time devoted to preflight antennal behavior were influenced by the presence of upwind infested or uninfested tomato leaves. However, these parameters were not affected by odors in the absence of visual plant stimuli. Our data provide a new view on foraging behavior of Dacnusa sibirica.     

Prey Habitat Location by the Cassava Mealybug Predator Exochomus flaviventris: Olfactory Responses to Odor of Plant, Mealybug, Plant–Mealybug Complex, and Plant–Mealybug–Natural Enemy Complex

Exochomus flaviventris Mader is considered to be the most active predator of the cassava mealybug Phenacoccus manihoti Matile–Ferrero in Central Africa. The response of experienced gravid female coccinellids to the odor of cassava plant (var. Zanaga), unparasitized mealybugs, plant–mealybug complex with or without feeding prey (parasitized or not), and plant–mealybug complex with or without conspecific coccinellids was investigated in a Y-tube olfactometer. The odor of uninfested cassava plants was not more attractive than clean air. Dual-choice tests revealed that mealybug-infested plants were preferred to mealybugs alone and mealybug-damaged plants and were the major sources of volatiles that attract females coccinellids to the microhabitat of its prey. The emission of volatile chemicals did not appear to be limited to the infested parts of the plant but did occur systemically throughout the plant. The presence of conspecific coccinellid larvae or adult males did not modify the attractiveness of the mealybug-infested plants. However, when an infested plant with conspecific predator females (alone or with conspecific males) was compared to an infested plant or infested plant with conspecific males, E. flaviventris females showed a preference for the last two sources of odor. The uninfested plant with conspecific males was also preferred to the uninfested plant with conspecific females. In addition, the odor of conspecific males was preferred over that of conspecific females. Female predators preferred the plant infested with unparasitized mealybugs over the plant infested with mealybugs previously parasitized. These results showed that E. flaviventris females use herbivore-induced plant volatiles during foraging and can detect via olfaction the presence of conspecific gravid females and parasitized prey, thus assessing patch suitability from a distance.     

Day vs. night predation on artificial caterpillars in primary rainforest habitats – an experimental approach

The influence of natural enemies has led to the evolution of various predator avoidance strategies in herbivorous insects. Many caterpillars are exclusively active at night and rest during the day. It is widely assumed that nocturnal activity in caterpillars reduces their risk of falling prey to their natural enemies. To test this hypothesis, we compared predation pressure between day and night in tree‐fall gaps and closed‐canopy forest sites in an Amazonian primary lowland rainforest. Artificial clay caterpillars, showing camouflaged colouration (green), were exposed as potential prey to a natural predator community. Attacks were significantly more frequent during daytime and were reduced by about a quarter at night in tree‐fall gaps, and by a third in closed‐canopy forest sites. This supports the idea of time‐dependent activity in caterpillars as an antipredatory adaptation. Further, independent of the time of day, predation pressure on caterpillars was significantly higher in tree‐fall gaps compared to closed‐canopy forest habitats. Nearly all predation events were caused by arthropods, whereas birds played a negligible role. Across both habitat types and time scales, ants acted as major predator group, emphasising their important role in population control of herbivorous insects in lowland rainforest ecosystems. This is the first experimental study using artificial caterpillars to examine whether time‐scheduling of exposition might influence predation risk amongst undefended, solitary, free‐living lepidopteran larvae.     

Can herbivore‐induced plant volatiles inform predatory insect about the most suitable stage of its prey?

The leaf beetle Plagiodera versicolora (Coleoptera: Chrysomelidae) is a specialist herbivore, all of whose mobile stages feed on the leaves of salicaceous plants. Both the larval and adult stages of the ladybird Aiolocaria hexaspilota (Coleoptera: Coccinellidae) are dominant natural enemies of the larvae of the leaf beetle. To clarify the role of plant volatiles in prey‐finding behaviour of A. hexaspilota, the olfactory responses of the ladybird in a Y‐tube olfactometer are studied. The ladybird adults show no preference for willow plants Salix eriocarpa that are infested by leaf beetle adults (nonprey) over that for intact plants but move more to the willow plants infested by leaf beetle larvae (prey) than to intact plants. Moreover, ladybird larvae show no preference for willow plants infested by leaf beetle larvae or adults over intact plants. Using gas chromatography‐mass spectrometry, six volatile compounds are released in larger amounts in the headspace of willow plants infested by leaf beetle larvae than in the headspace of willow plants infested by leaf beetle adults. In addition, the total amount of volatiles emitted from willow plants that are either intact or infested by leaf beetle adults is much smaller than that from willow plants infested by leaf beetle larvae. These results indicate that volatiles from S. eriocarpa infested by P. versicolora inform A. hexaspilota adults about the presence of the most suitable stage of their prey, whereas A. hexaspilota larvae do not use such information.     

Infochemical-Mediated Niche Use by the Predatory Mites Typhlodromalus manihoti and T. aripo (Acari: Phytoseiidae)

In Africa, Typhlodromalus manihoti and T. aripo, two introduced predators of the cassava green mite Mononychellus tanajoa, occupy different parts of cassava foliage. In the present study, niche use by these two predators, as mediated by prey-induced infochemicals, was investigated. In response to prey feeding damage, cassava plant parts emit volatile blends, that attract phytoseiidae predators. When given a choice between old cassava leaves infested with M. tanajoa and either apices or young cassava leaves infested with M. tanajoa, T. aripo displayed a marked preference for odors emitted from either infested apices or infested young leaves over infested old leaves but showed no preference for odors from apices versus young leaves, all infested with M. tanajoa. Typhlodromalus manihoti did not discriminate between volatiles from the three infested cassava plant parts. Our data show that T. aripo uses differences in volatile blends released by infested cassava plant parts and restricts its fundamental niche to a realized niche, which enables coexistence with its competitor T. manihoti.     

Insect herbivores and the nutrient flow from the canopy to the soil in coniferous and deciduous forests

Phytophagous insects can have severe impacts on forested ecosystems in outbreak situations but their contribution to flows of energy and matter is otherwise not so well known. Identifying the role of phytophagous insects in forested ecosystems is partly hindered by the difficulty of combining results from population and community ecology with those from ecosystem ecology. In our study we compared the effects of aphids and leaf-feeding lepidopterous larvae on the epiphytic micro-organisms in the canopies of spruce, beech and oak, and on the vertical flow of energy and nutrients from the canopies down to the forest floor. We particularly searched for patterns resulting from endemic herbivory rather than outbreak situations. Excreta of lepidopterous larvae and aphids promoted the growth of epiphytic micro-organisms (bacteria, yeasts, filamentous fungi) on needles and leaves, which suggests that micro-organisms were energy limited. Leachates from needles and leaves of infested trees contained higher concentrations of dissolved organic C and lower concentrations of NH₄-N and NO₃-N, relative to uninfested trees. The seasonal abundance of herbivores and micro-organisms significantly affected the dynamics of throughfall chemistry; for instance, concentrations of inorganic N were lower underneath infested than uninfested trees during June and July. There was little difference between the chemistry of soil solutions collected from the forest floor beneath infested and uninfested trees. Thus, under moderate to low levels of infestation the effects of above-ground herbivory seems to be obscured in the soil through buffering biological processes.     

Florivores on the dioecious shrub Eurya japonica and the preferences and performances of two polyphagous geometrid moths on male and female plants

Flowers of dioecious plants have sexually dimorphic traits that may affect florivore performances, and florivores may have preferences to plant sex that are correlated with their performance on different plant sexes. We investigated the florivory on a polygamodioecious evergreen shrub Eurya japonica in Japan to reveal florivores and their feeding patterns involved in sexually biased florivory on E. japonica flowers. Flowers of E. japonica were infested by lepidopteran and dipteran larvae and hemipteran insects. Lepidopteran larvae were chewers, dipteran larvae were gall makers and hemipteran insects were suckers. Chewed flowers were most frequent among infested flowers. Of florivores, lepidopteran larvae, mostly of Geometridae, were the important florivore that damaged flowers by chewing. Florivores infested male flower buds more often than female flower buds, but only a geometrid larvae Chloroclystis excise, which exclusively uses flower buds, showed the biased infection on male flowers. Rearing experiments for two other geometrid moths which use both leaves and flowers showed that the preference and performance of Ourapteryx nivea that fed mainly leaves did not differ between the plant sexes, whereas the development of Alcis angulifera larvae which fed both leaves and flowers was slower when they fed female than male leaves and flower buds. In addition, A. angulifera larvae fed fewer flower buds on female than on male plants. These results show that the male‐biased florivory on E. japonica trees is attributed mainly to the specialist florivore and also feeding preference for male flowers in an opportunistic florivore that feed both leaves and flowers.     

Comparison of volatile organic compounds from uninfested and Monochamus alternatus Hope infested Pinus massoniana Lamb.

Monochamus alternatus is a destructive stem‐boring herbivore of Pinus massoniana, and the principal vector of pine wood nematode. To investigate the impacts of boring by M. alternatus larvae on the emission of volatile organic compounds (VOCs) from their host trees, the VOCs from uninfested and M. alternatus larvae infested P. massoniana trees were observed using a gas chromatograph–mass spectrometer. We detected 12, 9, 18 and 14 volatile organic compounds from infested xylem, infested phloem, uninfested xylem and uninfested phloem, respectively. In P. massoniana xylem, the boring of M. alternatus larvae induced cyclosativene, and inhibited 4‐carene, humulene, styrene, α‐phellandrene, β‐myrcene, β‐phellandrene and γ‐terpinene. The relative amounts of camphene, copacamphene, longicyclene, longifolene, tricyclene and α‐longipinene were significantly increased, and the relative amounts of α‐pinene and β‐pinene were significantly decreased by the boring behaviors of M. alternatus larvae. In P. massoniana phloem, the boring of M. alternatus larvae induced 2‐bornanone, copacamphene, longicyclene and α‐longipinene, and inhibited 2‐carene, 4‐carene, styrene, α‐phellandrene, β‐myrcene, β‐phellandrene, β‐pinene, γ‐terpinene and ο‐cymene. The relative amounts of camphene, caryophyllene and longifolene were significantly increased by the boring behaviors of M. alternatus larvae. The results indicate that the boring behaviors of M. alternatus larvae changed both the sorts and contents of the VOCs from P. massoniana trees.     

Plant volatiles, rather than light, determine the nocturnal behavior of a caterpillar

Although many organisms show daily rhythms in their activity patterns, the mechanistic causes of these patterns are poorly understood. Here we show that host plant volatiles affect the nocturnal behavior of the caterpillar Mythimna separata. Irrespective of light status, the caterpillars behaved as if they were in the dark when exposed to volatiles emitted from host plants (either uninfested or infested by conspecific larvae) in the dark. Likewise, irrespective of light status, the caterpillars behaved as if they were in the light when exposed to volatiles emitted from plants in the light. Caterpillars apparently utilize plant volatile information to sense their environment and modulate their daily activity patterns, thereby potentially avoiding the threat of parasitism.     

Wheat stem sawfly‐infested plants benefit from parasitism of the herbivorous larvae

1 Parasitoids Bracon cephi (Gahan) and Bracon lissogaster Muesebeck and their herbivorous host the wheat stem sawfly Cephus cinctus Norton, a pest of wheat Triticum aestivum, were investigated for yield in T. aestivum grown in the field. 2 Wheat stem sawfly‐infested stems had a higher yield potential than uninfested stems. However, final reproductive output was not significantly different between ears on infested stems that supported complete larval development compared with ears on uninfested stems. 3 Stems containing parasitized larvae and stems containing larvae that died before completing their development had a higher mean number of seeds and seed weight, when accounting for number of fertile spikelets of each ear, than either infested with live larvae and uninfested stems. 4 The results obtained suggest that larval feeding prevented infested stems from attaining their yield potential, and that the negative impact of the pest on wheat yield was reduced when late instar sawfly larvae were parasitized. Even though some feeding occurs before parasitism, this early damage has a comparatively low impact on yield. 5 This is the first study to show a yield benefit and enhanced plant fitness due to the wheat stem sawfly parasitoids B. cephi and B. lissogaster. This results from the maintenance of increased seed number and seed weight in the higher yielding stems that are preferentially infested by this pest.     

Maize‐field complexity and farming system influence insectivorous birds’ contribution to arthropod herbivore regulation

The contribution of insectivorous birds to reducing crop damage through suppression of herbivory remains underappreciated, despite their role as cropland arthropod predators. We examined the roles of farming system, crop cover pattern, and structural configuration in influencing assemblage composition of insectivorous birds and their herbivorous arthropod prey across maize fields, and determined how bird exclusion affects crop herbivory levels. To achieve these objectives, we collected data across a sample of organic and conventional small‐scale non‐Bt maize farms in western Kenya. Assessments of abundance, diversity, and richness of insectivorous birds and abundance of their arthropod prey were compared between organic and conventional small‐scale non‐Bt maize on monocultured and inter‐cropped farms. We also employed bird exclusion experiments to assess impacts of bird predation on herbivorous arthropod abundance. Results showed that higher structural heterogeneity supported higher insectivorous bird richness, particularly under organic systems, dense trees, large woodlots, and thick hedgerows. Bird abundance further increased with crop diversity but not in relation to cropping method, hedgerow type, or percent maize cover per se. Conversely, herbivorous arthropod abundance and richness increased on conventional farms and those with higher percent maize cover, but were unaffected by cropping methods, tree, or hedgerow characteristics. Birds’ arthropod prey was more abundant under completely closed experimental plots compared with open or semi‐closed plots, confirming a significant linkage between birds and herbivorous arthropod suppression. In this study, we demonstrate importance of structural heterogeneity in agricultural landscapes, including diverse croplands and on‐farm trees to maximize insectivorous birds’ contribution to reducing crop arthropod herbivory. Abstract in Swahili is available with online material.     

Acaricides impair prey location in a predatory phytoseiid mite

The use of predatory mites as the sole management tactic in biological control programmes frequently does not fully and reliably prevents damage of phytophagous mites on plants. Therefore, as an alternative, the integration of predatory mites with acaricides can provide more effective control of phytophagous mites than that of the predators only. However, for such integration, acaricides minimal negative impacts on predatory mites are required. In this study, we evaluated the sublethal effects of three acaricides on the foraging behaviour of Neoseiulus baraki (Athias‐Henriot) (Acari: Phytoseiidae) in a coconut production system. The acaricides were assessed for interference with the location of prey habitat using a Y‐tube olfactometer and for interference with the location of the prey colony within the habitat using a video‐tracking system. In addition to the choice of odour source, the time required and the distance walked to make the choice were assessed. The acaricides tested were abamectin, azadirachtin and fenpyroximate. The predatory mite preferred coconuts infested with the coconut mite Aceria guerreronis Keifer (Acari: Eriophyidae) over uninfested coconuts when not exposed to acaricides. However, when exposed to acaricides, the predator did not distinguish between infested and uninfested fruits. When exposed to abamectin, N. baraki spent more time resting and walked greater distances before making the choice of an odour source. Thus, the acaricides impair the ability of the predatory mite N. baraki to locate a prey habitat and to locate a prey within that habitat. The acaricides differentially affected prey foraging by interfering with odour perception.     

Mixed blends of herbivore-induced plant volatiles and foraging success of carnivorous arthropods

Food webs are overlaid with infochemical webs that mediate direct and indirect interactions. Behavioural ecologists have extensively documented that carnivorous arthropods exploit herbivore-induced plant volatiles during foraging for herbivorous arthropods. Most studies on the role of infochemicals in multitrophic interactions have been conducted against an odour-free background, although field studies show that carnivores also use herbivore-induced plant volatiles under more complex conditions. Here we investigated the effect of mixing the blends of volatiles emitted by two plant species on the foraging behaviour of the predatory mite Phytoseiulus persimilis . This was done in an olfactometer under laboratory conditions and in a semi-field setup under greenhouse conditions. The olfactometer setup ensured directed mixing of the two odour blends, while odour mixing in the greenhouse setup was much less controlled and resulted from diffusion. In 4 out of 5 olfactometer experiments the behaviour towards volatiles from spider-mite ( Tetranychus urticae ) infested Lima bean plants was not affected by mixing with volatiles from caterpillar ( Pieris brassicae ) infested Brussels sprouts plants. In the fifth olfactometer experiment the response shifted significantly towards the volatiles from infested Lima bean leaves without volatiles from infested cabbage leaves. In the greenhouse setup no effect of infested cabbage plants or their volatiles on the location of spider-mite infested bean plants was recorded. The two odour blends used in this study, i.e. those from spider-mite infested Lima bean leaves and from caterpillar-infested Brussels sprouts plants, are very different and there is no overlap in compounds that are known to attract the predators. The results are discussed in the context of other types of odour-blend mixing and the effects on food web interactions.     

Olfactory responses of Cotesia flavipes (Hymenoptera: Braconidae) to target and non-target Lepidoptera and their host plants

The attraction of Cotesia flavipes Cameron to volatiles from a range of non-target lepidopteran larvae and their host plants (grasses and trees) or food substrate (honeycomb) was evaluated using a Y-tube olfactometer. The non-target host larvae used in the study included Galleria mellonella (L.), Charaxes cithaeron Felder, Bombyx mori L., and Eldana saccharina Walker. The target insects, Chilo partellus (Swinhoe) and Chilo orichalcociliellus (Strand), were used as controls. Host plants included Afzelia quanzensis Welw., Morus alba L., Cyperus papyrus L., Pennisetum purpureum Schumach, and Zea mays L. The response of C. flavipes to volatiles from the non-target larvae and their food was variable. Attraction to uninfested maize was not significantly different from uninfested plants of non-target hosts or honeycomb. Only maize and honeycomb were preferred over clean air. C. partellus infested maize plants were significantly more attractive than M. alba, A. quanzensis, and honeycomb infested with their herbivores. Infested maize and C. papyrus were more attractive than uninfested ones. When odors from naked larvae were tested, C. flavipes preferred odors from C. partellus larvae over those of E. saccharina and C. cithaeron and larvae of C. partellus and G. mellonella were preferred to clean air. The implications of these findings for biological control and its effect on non-target organisms are discussed.