Chemical Ecology of Fruit Bat Foraging Behavior in Relation to the Fruit Odors of Two Species of Paleotropical Bat-Dispersed Figs (<Emphasis Type="Italic">Ficus hispida</Emphasis> and <Emphasis Type="Italic">Ficus scortechinii</Emphasis>)

We investigated the fruit odors of two bat-dispersed fig species in the Paleotropics, in relation to the foraging behavior of fruit bats, to test the following hypotheses: 1) fruit odor plays a critical role for detection and selection of ripe figs by fruit bats; 2) bat-dispersed fig species are characterized by the same, or similar, chemical compounds; and 3) total scent production, in bat-dispersed figs, increases when fruits ripen. We performed bioassays to test the effect of both natural and synthetic fig fruit odors on the foraging behavior of the short-nosed fruit bat (Cynopterus brachyotis)—an important disperser of figs within the study area. Fruit bats responded to both visual and chemical (olfactory) cues when foraging for figs. However, the strongest foraging reaction that resulted in a landing or feeding attempt was almost exclusively associated with the presence of a ripe fruit odor—either in combination with visual cues or when presented alone. Fruit bats also used fruit odors to distinguish between ripe and unripe fruits. By using gas chromatography (GC) and GC/mass spectrometry (MS), a total of 16 main compounds were identified in the ripe fruit odor of Ficus hispida and 13 in the ripe fruit odor of Ficus scortechinii—including alcohols, ketones, esters, and two terpenes. Additional compounds were also recorded in F. hispida, but not identified—four of which also occurred in F. scortechinii. Total scent production increased in both species when fruits ripened. Both natural and synthetic fruit odors resulted in feeding attempts by bats, with no feeding attempts elicited by unscented controls. Reaction rates to natural fruit odors were higher than those to synthetic blends.     

Response to walnut olfactory and visual cues by the parasitic wasp Diachasmimorpha juglandis

Diachasmimorpha juglandis is a specialist parasitoid attacking fly larvae in the genus Rhagoletis that feed exclusively on walnut fruit husks. In a free-foraging assay comparing response to uninfested, infested, and mechanically damaged fruits, we first determined that D. juglandis use host feeding damage on the fruit as a cue for host presence. In another free-foraging assay that used artificial walnut models and wind tunnel experiments, D. juglandis distinguished infested from uninfested fruits by using either olfactory or visual cues separately. However, the response rate of wasps in the wind tunnel was raised considerably when visual cues were also available. We analyzed the volatile compounds emitted by cohorts of uninfested, mechanically damaged, and infested fruits 1, 3, 5, 8, and 10 days after oviposition by flies into the infested fruits. Total volatile emissions did not differ significantly among treatments, but quantitative changes in volatiles distinguished infested fruits from uninfested and damaged fruits. The fact that parasitoids did not distinguish between infested and damaged fruits in assays where damage was visible indicates that they rely on visual cues when those are available.     

Use of odor baits in traps to test reactions to intra- and interspecific chemical cues in house mice living in outdoor enclosures

House mice (Mus musculus) living in outdoor enclosures were tested for urinary chemical cue preferences using odor-baited traps. In the first experiment, with only volatile cues available, odors from conspecific males and females of various age classes and reproductive conditions were tested; no preferences were exhibited. In the second experiment mice had both nonvolatile and volatile cues available from the same sources as in experiment I. All age and sex class and female reproductive condition groups exhibited odor cue preferences except juvenile females. There were no specific odor cue preferences exhibited by any of the responder types with regard to odors from juvenile females. In the third and fifth experiments, mice were presented with nonvolatile plus volatile or only volatile urine odor cues, respectively, from four genera,Mus, Peromyscus, Microtus, andHomo. Mice of all age classes and both sexes preferredMus musculus odor, were neutral towardMicrotus ochrogaster odor, and avoided odors fromPeromyscus leucopus andHomo sapiens; these patterns were the same regardless of whether only volatile or both volatile and nonvolatile cues were presented. The fourth and sixth experiments involved testing volatile cues only and volatile cues plus nonvolatile cues from human sweat or feces from dogs, cats, or shrews. Mice avoided the human sweat and feces from cats and shrews, but were neutral toward the odor of dog feces. There were effects on whether mice were trapped in the interior of the enclosure or on the perimeter for some odors tested in these six experiments. The findings provide insights regarding possible functions of odor cues in the behavioral ecology of house mice. Odor-baiting traps can be an effective tool with respect to testing some, but not all questions pertaining to olfactory cues and house mouse social biology.     

Attraction of the Fruit-Eating Bat Carollia perspicillata to Piper gaudichaudianum Essential Oil

We performed field tests using mimetic Piper fruits with and without essential oil extracted through hydrodistillation from Piper gaudichaudianum ripe fruits in order to evaluate the role of odor in Carollia perspicillata attraction and capture in mist-nets. During the field tests, 26 C. perspicillata were captured, 21 (80.7%) in nets with the essential oil of P. gaudichaudianum and five (19.3%) in nets without oil. Other bat species, Artibeus spp. (67), which is specialized on fruits of Moraceae, and Sturnira lilium (10), specialized on those of Solanaceae, were also captured, but they exhibited no significant preference for nets with or without oil. We conclude that odor is pre-eminent over visual cues in food location by C. perspicillata in a field situation. Based on the result, we propose the extraction and use of essential oils of chiropterochoric fruits as a useful approach to improve autoecological studies on fruit-eating bats and to promote tropical forest restoration through the attraction of frugivorous bats to degraded areas.     

Attraction ofCarpophilus Spp. (Coleoptera: Nitidulidae) to volatile compounds present in figs

Various volatile compounds present in ripening figs were attractive toCarpophilus hemipterus, C. mutilatus, C.freemani, andC. lugubris. Field tests demonstrated that traps baited with a mixture of acetaldehyde, ethyl alcohol, and ethyl acetate caught more adultC. hemipterus than those baited with (1) other mixtures involving various combinations of 19 compounds, (2) with 16 single compounds, or (3) with fig paste.This investigation was supported in part by a grant from the California Dried Fig Advisory Board.     

Does the odor from sponges of the genus Ircinia protect them from fish predators?

Caribbean sponges of the genus Ircinia contain high concentrations of linear furanosesterterpene tetronic acids (FTAs) and produce and exude low-molecular-weight volatile compounds (e.g., dimethyl sulfide, methyl isocyanide, methyl isothiocyanate) that give these sponges their characteristic unpleasant garlic odor. It has recently been suggested that FTAs are unlikely to function as antipredatory chemical defenses, and this function may instead be attributed to bioactive volatiles. We tested crude organic extracts and purified fractions isolated from Ircinia campana, I. felix, and I. strobilina at naturally occurring concentrations in laboratory and field feeding assays to determine their palatability to generalist fish predators. We also used a qualitative technique to test the crude volatile fraction from I. felix and I. strobilina and dimethylsulfide in laboratory feeding assays. Crude organic extracts of all three species deterred feeding of fishes in both aquarium and field experiments. Bioassay-directed fractionation resulted in the isolation of the FTA fraction as the sole active fraction of the nonvolatile crude extract for each species, and further assays of subfractions suggested that feeding deterrent activity is shared by the FTAs. FTAs deterred fish feeding in aquarium assays at concentrations as low as 0.5 mg/ml (fraction B, variabilin), while the natural concentrations of combined FTA fractions were >5.0 mg/ml for all three species. In contrast, natural mixtures of volatiles transferred from sponge tissue to food pellets and pure dimethylsulfide incorporated into food pellets were readily eaten by fish in aquarium assays. Although FTAs may play other ecological roles in Ircinia spp., these compounds are effective as defenses against potential predatory fishes. Volatile compounds may serve other defensive functions (e.g., antimicrobial, antifouling) but do not appear to provide a defense against fish predators.     

Olfactory discrimination ability in short-tailed fruit bat,carollia perspicillata (Chiroptera: Phyllostomatidae)

The olfactory discrimination ability in a fruit-eating bat,Carollia perspicillata, was investigated. In a food-rewarded flight training procedure, four animals were taught to choose one of two odors simultaneously presented in a three-choice apparatus.Carollia chose the odor of ripe banana over that of unripe banana in a spontaneous choice test. With the same method, the bats significantly preferred undiluted banana odor compared to a dilution of 1 10, but did not express a preference between undiluted and 15 dilutions of ripe banana. In a series of reinforced choice tests, the positive stimulus (CS +) was the standardized odor of natural ripe banana. Prominent components of this complex odor were used as CS –, first in monomolecular form and later in combinations (odor cocktails) of increasing similarity to banana odor. In all these tests the bats easily discriminated the natural food odor from the artificial ones. Even a gas Chromatographic congruity of 57% between the major components of natural banana odor and an odor cocktail caused no impairment of the olfactory performance. The olfactory discrimination ability ofCarollia perspicillata supports the assumption that echolocating, frugivorous bats may use their sense of smell to find and select their food.     

Chemical stimuli in host-habitat location byLeptopilina heterotoma (Thomson) (Hymenoptera: Eucoilidae), a parasite ofDrosophila

Chemical stimuli play an important role in the process of searching for a host habitat by parasitic wasps. Volatile compounds originating from host habitats and/or hosts are the cues that enable such a location.Leptopilina heterotoma, a larval parasite ofDrosophila, is attracted to the food of its host, baker's yeast. Analysis of the fermentation products of baker's yeast, using a mass spectrometer, and olfactometer studies indicate that three fermentation products of this yeast, the main component of the host habitat in our laboratory, attractL. heterotoma: ethanol (5%), ethyl acetate (10^–2, 10^–3%), and acetaldehyde (1%). A combination of these three compounds, however, cannot compete with baker's yeast in attracting the parasites. Thus other factors, such as different compounds, concentrations, and/or combinations, also, play a role and remain to be tested.Leptopilina heterotoma does not use host-related olfactory cues in long-distance habitat location as it cannot distinguish between host habitat and host habitat with hosts.     

Deterrence of repeated oviposition by fruit-marking pheromone inCeratitis capitata (Diptera: Tephritidae)

During ovipositor dragging on the fruit surface following egg laying in hawthorne fruit,Ceratitis capitata (Wiedemann) females deposit an unidentified pheromone that deters repeated oviposition attempts in that fruit. The pheromone proved water soluble and, when collected and sprayed in aqueous solution onto uninfested fruits in laboratory cages, effectively deterred boring attempts byC. capitata females of wild origin for at least 6 days (termination of test). A laboratory population ofC. capitata cultured on artificial media for more than 200 generations deposited pheromone that proved equally as deterrent to wild fly oviposition as pheromone from wild flies. However, lab fly oviposition was not effectively deterred by the presence of pheromone. The ecological significance of the pheromone is discussed.     

Identification of food volatiles attractive toGlischrochilus quadrisignatus andGlischrochilus fasciatus (Coleoptera: Nitidulidae)

Seven volatile compounds identified from the headspace of whole wheat bread dough were investigated for their role in attractingGlischrochilus quadrisignatus andG. fasciatus in the field. Traps baited with either whole wheat bread dough or a synthetic seven-component bread dough odor caught similar numbers of these beetles, suggesting that the seven-compound combination could simulate the behavioral effect of bread dough. A series of trials using traps baited with various combinations of these chemicals showed that five compounds were significantly active in attractingG. quadrisignatus andG. fasciatus, but not all were essential for maximum response. The simplest blend eliciting a level of response comparable to the seven-component combination included ethyl acetate, acetaldehyde, ethanol, and racemic 2-methylbutanol, of which ethyl acetate, ethanol, and acetaldehyde were essential and 2-methylbutanol was replaceable with 2-methylpropanol forG. quadrisignatus attraction. Ethyl acetate and ethanol were essential for comparable attraction ofG. fasciatus. The chemical mediation of food finding in G.quadrisignatus andG. fasciatus is discussed in the context of volatile blends characterized for other nitidulid species.     

Trirhabda canadensis (Coleoptera: Chrysomelidae) responses to plant odors

The responses of the goldenrod leaf beetleTrirhabda canadensis to host and nonhost volatile odors were tested in a Y-tube olfactometer in the laboratory. Beetles preferred host to nonhost odors and were sensitive to concentrations of host odor. Beetles distinguished between host and nonhost volatiles of only one of the two nonhostSolidago species; host volatiles were preferred to all nonhost volatiles at the family and order levels. In other words, all nonhosts above the genus level had similar effects on beetle responses. Although the odors of most nonhosts were neutral (i.e., neither attractive nor repellent) to the beetles as tested against air, this neutrality disappeared if the odors of two or more nonhosts were added to the host odor and beetles were given a choice between this mixture and pure host odor. Given this choice, they strongly preferred pure host odor, which suggests that diversity of odors per se is unattractive to the beetles. Beetles walked rather than flew to locate their hosts in the field, and their movements suggest that they used olfactory cues to locate hosts.     

Chemical characterization of fruit and fungal volatiles attractive to dried-fruit beetle,Carpophilus hemipterus (L.) (Coleoptera: Nitidulidae)

The chemical basis underlying orientation to fruit and fungal odors was investigated for the dried-fruit beetle,Carpophilus hemipterus (L.). In wind-tunnel bioassays of walking and flight response from 1.8 m, beetles were attracted to odors of the yeastSaccharomyces cerevisiae on agar, aseptic banana, or banana inoculated withS. cerevisiae, although both banana substrates elicited greater response than the yeast alone. When presented in a two-choice bioassay, the yeast-inoculated banana attracted approximately twice as many beetles as did the aseptic banana. GC-MS analysis of the headspace volatiles above these odor sources revealed a somewhat more complex and concentrated volatile profile for yeast-inoculated banana than for aseptic banana. The odor from yeast on agar had fewer components, and these were present at lower concentrations than the odors of either banana substrate. By blending mineral-oil or aqueous solutions of the 18 components of inoculated-banana odor in varying concentrations, it was possible to mimic closely the headspace profile of the natural odor. This synthetic odor also elicited beetle attraction in the wind tunnel at levels comparable to the inoculated banana. Through a series of bioassays in which individual components were subtracted from or added to a synthetic odor blend, it was determined that ethyl acetate, acetaldehyde, 2-pentanol, and 3-methylbutanol comprised the simplest blend of compounds evoking full behavioral response. However, 2-methylpropanol or butanol were apparently interchangeable with 3-methylbutanol in this blend, and comparable response could also be elicited by replacing acetaldehyde with a combination of both 2-pentanone and 3-hydroxy-2-butanone. Thus, our results suggest that this generalist insect herbivore locates its hosts by a long-range response to a variety of blends of common fruit volatiles, whose concentrations are enhanced by fungi.     

Responses of the Pollinating Wasp Ceratosolen solmsi marchali to Odor Variation Between Two Floral Stages of Ficus hispida

During development of figs on Ficus hispida, only the female floral stage is receptive to its pollinator Ceratosolen solmsi marchali. After this stage, the quantity of fig odor decreases. The effects of F. hispida volatiles from receptive figs (figs at the female floral stage, when they are pollinated) and interfloral figs (between the female floral and male floral stages) on their pollinator were studied, together with responses to compounds present in the odor. Odors emitted by both receptive and interfloral figs were attractive to the pollinator. However, wasps preferred the odor of receptive figs to that of interfloral figs even though the quantity of interfloral volatiles increased. Three monoterpenes that included linalool (major constitutent) and two minor compounds limonene and β-pinene from the receptive fig volatiles were used to test the pollinator responses. The levoisomer and racemic mixtures of linalool were attractive to the pollinator at high doses, but the dextroisomer was neutral. (±)-Limonene and (−)-β-pinene at high doses were even less attractive to the pollinator than clean air and were neutral at low doses, while (R)-(+)-, (S)-(−)-limonene were neutral at all doses. In blend tests, all four mixtures of (±)-linalool or (S)-(−)-linalool combined with (±)-limonene or (−)-β-pinene attracted C. solmsi marchali when administered at high doses. (R)-(+)-linalool and (−)-β-pinene enhanced the attractiveness of (S)-(−)-linalool to the pollinator, while enantiomers of limonene did not. These results suggest that both quality and quantity of fig volatiles regulate C. solmsi marchali response and that quality is the main host-finding and floral stage-distinguishing cue for the pollinator. Synergistic effects of some compounds may play a role in enhancing attractiveness of the active compounds.     

Host odor and visual stimulus interaction during intratree host finding behavior ofRhagoletis pomonella flies

Responses ofRhagoletis pomonella (Walsh) (Diptera: Tephritidae) flies to host fruit visual stimuli (apples or models of apples) and chemical stimuli (synthetic apple volatile blend) were studied in semidwarf field-caged apple trees. Three different fruit or model densities (1, 4, or 16 fruit or models/ tree) and two odor release rates [ca. 0.7g/hr (close to the natural release rate of a ripe apple) and ca. 500g/hr (amount of odor released by commercially sold apple maggot traps)] were tested. Individually released flies were followed as they moved within a tree for a maximum of 20 min. We recorded three-dimensional search paths followed by foraging flies and computed such variables as total relative distance traveled before alighting on a fruit or model, track length between individual alightment sites, and directness of flight to fruits or models. Effect of odor on propensity to alight on fruit or models and host-searching behavior prior to alighting on fruit or on models varied according to fruit or model color and density. If the fruit visual stimulus was strong (e.g., red color), odor did not increase the probability of finding fruit or fruit models. As the visual stimulus became progressively weaker (red to green to clear), odor (irrespective of concentration) appeared to aid flies during the fruit-finding process. As density of fruit or models increased, the probability of flies finding a fruit or model also increased (e.g., 50% of flies found a red fruit model at 1 model/tree while 90% found a red model at 16 models/tree; 4% of flies found a clear model with odor at 1 model/tree while 35% found a clear model with odor at 16 models/tree). Findings reported elsewhere indicate thatR. pomonella flies are able to discover a point source of odor (an odor-bearing tree in a patch of trees) by flying upwind (in the tree patch) in response to intermittent exposure to odor. Findings here indicate that after arrival on a host tree (point source), flies discover individual apparent and abundant host fruit on the basis of vision. If fruit are less apparent or scarce, odor appears to interact with vision during the fruit-finding process.     

Fruit Odor as A Ripeness Signal for Seed-Dispersing Primates? A Case Study on Four Neotropical Plant Species

Fleshy fruits contain a myriad of secondary metabolites that may fulfill various non-mutually exclusive ecological functions. Among them are defense against pathogens and herbivores, manipulation of frugivores’ gut retention time, or controlling the germination process. In addition, it has been suggested that aroma compounds may be used as fruit-selection cues by frugivores, and that plants may be under selection to provide a reliable signal for ripeness to seed-dispersal vectors through ripe fruit aroma. A previous project demonstrated that fruit odor of two Neotropical primate-dispersed plant species can be used by primates to identify ripe fruits. Here, we provide data supporting the hypothesis that olfactory conspicuousness of ripeness in these two species may be an evolved signal rather than a cue exploited by primates. We analyzed the odors of ripe and unripe fruits of the two species along with odors of two sympatric species whose main dispersal vector is passerine birds. We show that only primate-dispersed species significantly change their odor profiles upon ripening. Thus, odor of bird-dispersed species is not informative regarding their ripeness level and is likely to fulfill other functions. We discuss these data in light of the multiple hypotheses for the presence of fruit secondary metabolites, and we offer a roadmap for future studies to establish the hypothesis that fruit odor is an evolved signal for ripeness.     

Volatiles from Ficus hispida and Their Attractiveness to Fig Wasps

Volatile compositions of receptive (ready to be pollinated), postpollinated, and postparasitized figs, and leaves of Ficus hispida were analyzed. Differences among them were examined, and the specificity of fig wasp attractiveness was investigated. Linalool was the major constituent of steam-distilled oil of either male or female receptive figs, while dibutyl phthalate was the major compound of the oils of postparasitized and postpollinated figs. In petroleum ether extracts, palmitic oil, and 9,12-octadecadienoic acid were the main constituents of male and female receptive figs, while hexadecanoic acid ethyl ester was the major compound of postparasitized and postpollinated figs. In dichloromethane extracts, linalool was the major constituent of male and female receptive figs, 1-hydroxylinalool was the major component of male postparasitized figs, and 1-hydroxylinalool and benzyl alcohol were the major constituents of female postpollinated figs. Bioassays with sticky traps showed that Ceratosolen solmsimarchal was attracted to dichloromethane extracts of male and female receptive figs and to petroleum ether extracts of female receptive figs, but was not attracted to dichloromethane and petroleum ether extracts of male postparasitized and female postpollinated figs. Figs were attractive to pollinating wasps only at the receptive stage. The volatile constituents of receptive figs were different from those of postpollinated or postparasitized figs. From a receptive to a postpollinated state, figs changed in their volatile composition. Some compounds disappeared or decreased in amount. These include linalool, linalool oxide, -terpeneol, and 2,6-dimethyl-1,7-octadiene-3,6-diol, which may act as the attractants of the wasps. Others increased in amount, or several additional chemicals appeared. These include dibutyl phthalate, 1-hydroxylinalool, and benzyl alcohol, which may be repellents of the wasps. That dichloromethane extracts of male and female receptive figs showed similar activities in attracting fig wasps indicates that receptive figs of both sexes are similarly attractive to fig wasps, which is further supported by their similar volatile composition. Leaf extract was not attractive to the wasps.     

Do Fruit Ripening Volatiles Enable Resource Specialism in Polyphagous Fruit Flies?

Frugivorous tephritid fruit flies have lineages with high levels of host generalism. These insects use olfaction to locate fruits, but how they are able to recognize the odors of so many different host species is poorly understood. We used a series of behavioral experiments to investigate the role of fruit ripening volatiles as host cues in the Queensland fruit fly, Bactrocera tryoni (Froggatt), a polyphagous pest in Australia. Odors of mature guava (Psidium guajava) attracted female and male flies more strongly than three other ripening stages and guava pulp. We analyzed volatiles from guava odor and selected eleven compounds, all of which elicited an electrophysiological response in the antenna of female flies. Three of these, ethyl acetate, ethyl butyrate, and ethyl propionate, were released at the highest rates from the most attractive ripening stage. In behavioral trials, these three esters were not attractive individually, whereas a combination was necessary and sufficient in attracting female flies. The three-component blend was as attractive as the entire 11-component blend, which without these key volatiles was not attractive. Moreover, injecting low ranking hosts (squash and cucumber) with the three volatiles increased attraction in ovipositing female flies. These fruit flies are classed as generalists, but like many polyphagous insects they could be regarded as resource specialists, preferring specific plant reproductive stages with predictable odor cues. Exploring olfaction from this perspective could improve our understanding of host choice in polyphagous insects, and the selection of volatiles to be used as attractants in insect pest management.     

Responses of fig wasps to host plant volatile cues

Fig wasps (Chalcidoidea; Agaonidae) are intimately associated with the 750 or so species of fig trees (Ficus, Moraceae). Each tree species is usually pollinated by a single species of wasp belonging to the subfamily Agaoninae, while other wasps of the family are parasitoids or seed predators. Previous experiments have shown that the wasps are attracted to the trees by volatiles emanating from the figs. Using fig-bearing trees and arrays of sticky traps baited with figs, we investigated the specificity of wasp attraction and its timing. The pollinators of two closely relatedFicus species were specifically attracted to figs of their host species and only at the time when figs were ready to be pollinated. Some nonpollinating fig wasps appear to respond to the same volatile cues.     

Defining Sources of Coffee Plant Odor Attractive toCeratitis Capitata Flies

We evaluated attraction of released mature laboratory-cultured Mediterranean fruit flies to different sources of coffee plant odor placed in potted nonfruiting guava trees in outdoor field cages. Volatiles from crushed medium or dark red fruit ofCoffea arabica cv. arabica plants were significantly more attractive than volatiles from cut leaves or stems of such plants, volatiles from less-ripe crushedC. arabica fruit, and volatiles from crushed red fruit ofC. racemosa,C. canephora, orC. dewevari. Volatiles fromC. arabica cv. arabica crushed red fruit were equally attractive as volatiles from crushed red fruit ofC. congensis orC. arabica cv. mundo, cv. bourbon, cv. kents or cv. catura. Volatiles from as little as 2 g of crushed redC. arabica fruit (= 1 fruit) were as attractive as volatiles from 32 g of such fruit, demonstrating sensitivity of the bioassay approach used to a small amount of source material. Odor ofC. arabica red fruit refrigerated for 1–10 days after picking was significantly more attractive than odor of fresh-picked fruit, while odor of a 24-hr water extract of intact redC. arabica fruit was significantly more attractive than odor of 24-hr extracts of such fruit with methanol, methylene chloride, or hexane or 1- or 6-hr extracts with water. Extraction studies suggested that at least some of the volatiles of red coffee fruit attractive to medflies may be polar water-soluble molecules. In our final test, volatiles from crushed redC. arabica fruit trapped on Super Q and eluted with methylene chloride proved just as attractive as volatiles emanating directly from crushed fruit of the same type. Together, our findings define optimal source material and effective handling procedures of source material for future identification of volatile components of coffee fruit attractive to medflies.     

Folivory in Fruit Bats: Leaves Provide a Natural Source of Calicum

Leaves are an important dietary source of carbohydrates and protein, and an especially rich source of calcium for bats. Most studies of leaf eating by fruit bats have suggested that only male bats feed on leaves. In this study, 23 wild-caught Tongan fruit bats (Pteropus tonganus) were used in feeding trials conducted in an outdoor enclosure. The number of leaves and percentage of each leaf eaten were recorded for each bat on a daily basis, and these data were then multiplied by a calcium constant that was derived from a chemical analysis of leaves from Callophylum neo-ebudicum. Leaves of C. neo-ebudicum that were available in the enclosure were consumed by 82.7% of the bats. Overall, males consumed leaves in greater quantities and with higher frequency than females. Bats that consumed leaves on a regular basis consumed up to 46% more calcium to their diet compared with bats that did not regularly consume leaves. Leaves may represent a readily available, widely used, concentrated source of minerals for foraging bats, and have the potential to contribute significantly to the total amount of ingested calcium.