Defensive secretion of first-instar larvae of rootstalk borer weevil,Diaprepes abbreviatus L. (Coleoptera: Curculionidae), to the fire-antSolenopsis geminata (F.) (Hymenoptera: Formicidae)

Since several species of predatory ants show some kind of repulsion towards the first-instar larvae (FIL) ofDiaprepes abbreviatus L., the predatory behavior ofSolenopsis geminata (F.), a common ant in the citrus groves in Guadeloupe, was studied. Different extracts of larvae were disposed on egg masses ofD. abbreviatus and presented as prey to the ants, both in the field and in the laboratory. The ants are repelled by the FIL extracts. The allelochemicals involved are produced in large amounts, from 5 to 20 ng per larva. Physiochemical analyses have led to the identification of two sesquiterpenes of molecular weight 218 and 234, secreted in the respective proportions of 65 and 35%.     

Dorsal abdominal glands in nymphs of southern green stink bug,Nezara viridula (L.) (heteroptera: Pentatomidae): Chemistry of secretions of five instars and role of (E)-4-oxo-2-decenal,compound specific to first instars

We investigated the exocrine secretions from the five nymphal instars in the southern green stink bug,Nezara viridula, by analyzing separately the contents of the three dorsal abdominal reservoirs. All DAGs 1 produced a mixture of five alkanes with 12, 13, 14, 15, and 16 carbons. No differences were found between DAGs 2 and DAGs 3, for the five instars: the glands of first instars produce the same alkanes as DAGs 1,n-tridecane, traces of (E)-2-decenal, and a specific compound: (E)-4-oxo-2-decenal. In the other instars (second to fifth), (E)-4-oxo-2-decenal is absent from the secretion but another compound is present: (E)-4-oxo-2-hexenal. The kinetics of production of the different compounds were studied, the maximum amounts produced occurring 36 hr after hatching. The biological function of (E)-4-oxo-2-decenal was investigated. Using olfactometry, we showed that this compound acts as an attractant and an arrestant on second instars, at physiological doses. Moreover, this semiochemical was shown to be repellent to the fire-antSolenopsis geminata, a potential predator ofN. viridula and we established the dose-response curve for the repellent activity.     

1-Octen-3-ol together with geosmin: new secretion compounds from a polydesmid millipede,Niponia nodulosa

The small millipede Niponia nodulosa (Polydesmida: Cryptodesmidae) emits an earthy smell when disturbed. This smell was obtained from hexane extracts from both sexes at the sixth and seventh instars and adult stages, and was found by GC/MS analyses to be composed of two compounds, 1-octen-3-ol as the major component and geosmin as the minor component. This is the first report of these compounds in secreted substances from millipedes. As they showed little repellent activity against foraging ants in bioassays, their biological function as defensive allomones was not clearly elucidated. However, both compounds provoked negative chemotaxis of conspecific millipedes in a Y-tube olfactometer, especially 1-octen-3-ol, which was active at a dose equivalent to the content of a single millipede. Such biological activity suggests that this compound is involved in intraspecific communication in this millipede and may play a role as an alarm pheromone.     

Ant repellent effect of the sternal gland secretion ofPolistes dominulus (Christ) andP. sulcifer (Zimmermann). (Hymenoptera: Vespidae)

The long-chain carboxylic acids identified in the sternal gland secretion ofPolistes dominulus andP. sulcifer females were tested individually on three species of ants,Crematogaster scutellaris, Formica cunicularia, andLasius sp., in order to verify if they have a repellent effect. The unsaturated acids (palmitoleic, linoleic, and oleic) act as repellents of all three ant species, while the saturated acids (lauric, myristic, palmitic, and stearic) have no effect. The mixture reproducing the secretion of the sternal glands ofP. dominulus maintained its repellency for at least four days.     

Identity and Function of Scent Marks Deposited by Foraging Bumblebees

Foraging bumblebees can detect scents left on flowers by previous bumblebee visitors and hence avoid flowers that have been depleted of nectar. Tarsal secretions are probably responsible for this repellent effect. The chemical components of the tarsal glands were analyzed by combined gas chromatography–mass spectrometry for three species of bumblebee, Bombus terrestris, B. lapidarius, and B. pascuorum. The hydrocarbons identified were similar for each species, although there were interspecific differences in the relative amounts of each compound present. The tarsal extracts of all three species comprised complex mixtures of long-chain alkanes and alkenes with between 21 and 29 carbon atoms. When B. terrestris tarsal extracts were applied to flowers and offered to foraging bumblebees of the three species, each exhibited a similar response; concentrated solutions produced a repellent effect, which decreased as the concentration declined. We bioassayed synthetic tricosane (one of the compounds found in the tarsal extracts) at a range of doses to determine whether it gave a similar response. Doses 10^–12 ng/flower resulted in rejection by foraging B. lapidarius. Only when 10^–14 ng was applied did the repellent effect fade. We bioassayed four other synthetic compounds found in tarsal extracts and a mixture of all five compounds to determine which were important in inducing a repellent effect in B. lapidarius workers. All induced repellency but the strength of the response varied; heneicosane was most repellent while tricosene was least repellent. These findings are discussed in relation to previous studies that found that tarsal scent marks were attractive rather than repellent.     

Neotropical ant gardens

In ant gardens of lowland Amazonia, parabiotic ant speciesCamponotus femoratus andCrematogaster cf.limata parabiotica cultivate a taxonomically diverse group of epiphytic plants, whose establishment is restricted to arboreal carton ant nests. Epiphyte seeds are collected by workers ofCa. femoratus, the larger of the two ants, and stored unharmed in brood chambers where they subsequently germinate. Although seeds of some ant-garden epiphytes bear nutritional rewards, previous studies have shown that these rewards are not sufficient to explain the pattern of ant attraction to seeds. Five aromatic compounds occur frequently in and on the seeds of most ant-garden epiphytes and may be chemical cues by which ants recognize propagules of their symbiotic plants. The most widely distributed of these is methyl 6-methylsalicylate [6-MMS]1, previously reported as a major mandibular gland product in relatedCamponotus species and present in trace quantities inCa. femoratus males. (–)-Citronellol6 (previously unreported inCamponotus) was the principal volatile constituent in extracts of male heads, and (–)-mellein7 was present in small quantities. Discovery of 6-MMS inside the mandibular glands of maleCa. femoratus (and its presence in analogous glands of related ants) offers preliminary support for Ule's (1906) hypothesis that seeds attract ants by mimicking ant brood. In addition, the likely fungistatic activity of seed compounds suggests that they could retard microbial pathogens of ants and plants in the organic detritus of nest gardens. While the presence of identical seed compounds in so many unrelated plant lineages might represent a remarkable case of convergent evolution, other interpretations are possible.     

Shield Defense of a Larval Tortoise Beetle

Larvae of the folivorous tortoise beetle, Plagiometriona clavata, carry shields formed from feces and exuviae above their bodies. We used an ecologically relevant predatory ant, Formica subsericea, in a bioassay to determine if shields functioned as simple barriers, as previous studies indicated, or whether they were chemical defenses. Shields were necessary for larval survival; shield removal rendered larvae vulnerable. Shields produced by larvae reared on a substitute diet failed to provide protection. Solvent-leached shields also failed to deter ants, indicating the shield had a host-derived chemical component likely located in the feces, not in the exuviae. Solanum dulcamara, the larval host plant, contained free phytol, steroidal glycoalkaloids, and saponins. Shields contained partially deglycosylated metabolites of host steroidal glycoalkaloids and saponins, a suite of fatty acids, and derivatives of phytol, which together formed a deterrent barrier against ant attack. We compared the mobile shield of P. clavata to the stationary shield of another S. dulcamara-feeding leaf beetle, Lema trilinea. Both larval shield defenses were formed from a very similar array of host-derived compounds with deterrent properties. We concluded that convergent patterns of limited chemical transformation and selective incorporation of particular deterrent metabolites in shield defenses of two unrelated taxa represented responses to selection from invertebrate predators.     

Defense by Volatiles in Leaf-Mining Insect Larvae

The defense strategy of an insect toward natural enemies can include a trait that appears at first sight to contradict its defensive function. We explored phylogeny, chemistry, and defense efficiency of a peculiar group of hymenopteran sawfly larvae where this contradiction is obvious. Pseudodineurini larvae live in leaf mines that protect them from some enemies. Disturbed larvae also emit a clearly perceptible lemon-like odor produced by ventral glands, although the mine hampers the evaporation of the secretion. The mine could also lead to autointoxication of a larva by its own emitted volatiles. Citral was the major component in all Pseudodineurini species, and it efficiently repels ants. We conclude that full-grown larvae that leave their mine to pupate in the soil benefit from citral by avoiding attacks from ground-dwelling arthropods such as ants. In some species, we also detected biosynthetically related compounds, two 8-oxocitral diastereomers (i.e., (2E,6E)- and (2E,6Z)-2,6-dimethylocta-2,6-dienedial). Synthetic 8-oxocitral proved to be a potent fungicide, but not an ant repellent. The discrete distribution of 8-oxocitral was unrelated to species grouping in the phylogenetic tree. In contrast, we discovered that its presence was associated with species from humid and cold zones but absent in species favoring warm and dry environments. The former should be protected by 8-oxocitral when faced with a fungal infestation while crawling into the soil. Our work shows the importance of integrating knowledge about behavior, morphology, and life history stages for understanding the complex evolution of insects and especially their defense strategies.     

Role of volatile inforchemicals emitted by feces of larvae in host-searching behavior of parasitoidCotesia rubecula (Hymenoptera: Braconidae): A behavioral and chemical study

The role of volatile infochemicals emitted by feces of larvae in the host-searching behavior of the parasitoidCotesia rubecula was evaluated during single- and dual-choice tests inside a wind tunnel. The following treatments were tested: feces produced by second and fourth instars ofPieris rapae (preferred host), second instars ofP. brassicae (inferior host), second instars ofP. napi (nonhost), and wet feces of second instars ofP. rapae. During a single-choice situation females ofC. rubecula oriented to all types of feces tested. When a preference was to be made,C. rubecula preferred feces of second instars ofP. rapae over that of fourth, feces ofP. rapae over that ofP. brassicae, feces ofP. napi over that ofP. brassicae, and wet over normal host feces. No preference was exhibited between feces of second instars ofP. napi and that of second instars ofP. rapae. The relative importance of infochemicals from host feces versus plant damage caused by host larvae to the searching behavior ofC. rubecula was also evaluated. Plant damage was more important to the searching females than host feces when feces were present in specific concentrations in relation to damage. The volatiles released by normal and wet feces of second instars ofP. rapae, wet feces of fourth instars ofP. rapae, and normal and wet feces ofP. brassicae were collected and identified. Overall, 85 chemical compounds were recorded belonging to the following chemical groups: alcohols, ketones, aldehydes, esters, isothiocyanates, sulfides, nitriles, furanoids, terpenoids and pyridines. The blend of chemicals emitted by feces of different instars ofP. rapae and different species ofPieris exhibited an instar and species specificity in both quantity and quality. Wetting of normal feces increased the amount of volatile chemicals released, and it was also responsible for the appearance of new compounds. The role of feces of larvae in the host-seeking behavior ofC. rubecula is discussed.     

Chemical and experiential basis for rejection ofTropaeolum majus byPieris rapae larvae

Rejection of nasturtium,Tropaeolum majus, by cabbage-reared larvae ofPieris rapae has been explained by the presence of feeding deterrents in the nastrutium foliage. Sensitivity to the deterrents develops as neonate larvae feed on cabbage. The most prominent deterrent compound, which is present in nasturtium at a concentration of 40 mg/100 g fresh leaves, was identified as chlorogenic acid. When neonate larvae were fed on a cabbage leaf treated with high concentrations of deterrent-containing extracts of nasturtium foliage, they remained insensitive to the deterrents, so they accepted nasturtium when transferred as second instars. When neonate larvae were reared on a cabbage leaf treated with 0.1 mg chlorogenic acid, ca. 35% of the second instars accepted nasturtium. Similar dietary exposure of neonates to the subunits of chlorogenic acid, caffeic acid and quinic, acid resulted in much less or no effect on the rejection behavior of second instars. The results suggest that the combined effects of specific chemical constituents of nasturtium can explain the rejection of this plant by larvae ofP. rapae, but if larvae are continuously exposed to these compounds immediately after hatching, they apparently become habituated to the feeding deterrents. The lack of activity of the subunits of chlorogenic acid suggests that specific structural features are necessary for a dietary constituent to cause such habituation or suppression of sensitivity development.     

Plant-Derived Semiochemicals as Contact Host Location Stimuli for a Parasitoid of Leafminers

We elucidated the source of chemical cues in a system where the host is concealed and the parasitoid has no direct contact with the host larvae or its frass. Behavioral bioassays with Pholetesor bicolor, a larval parasitoid of the apple leafminer, Phyllonorycter pomonella, showed that the herbivore-damaged leaf epidermis (mine) elicited ovipositional probing of parasitoid females. Probing on larvae or frass was seldom observed. Hexane extracts of mines elicited the same ovipositional probing behavior while no response was observed with hexane extracts of larvae or frass or with methanol and diethyl ether extracts. In addition, gas chromatographic analyses showed qualitatively and quantitatively different profiles of these three components of the host-plant complex. By far the highest quantities and also the highest number of compounds was recovered from mine extracts. Identified compounds in the mine included six alkanes (n-C ₂₇ to n-C ₃₃) and squalene (C₃₀H₅₀). A synthetic blend of the seven compounds was slightly less active in biotests than the equivalent natural blend, as shown by a time delay in female response. We conclude that this leafminer parasitoid does not rely on host-derived kairomones but instead uses plant-derived semiochemicals for host location and ovipositional probing behavior.     

Newly Hatched Neonate Larvae Can Glycosylate: The Fate of Betula pubescens Bud Flavonoids in First Instar Epirrita autumnata

Betula pubescens bud flavonoid aglycones reportedly have negative effects on the performance of first instar Epirrita autumnata and, thus, may defend birch leaves from larval defoliation. We hypothesized that the detrimental effects of these lipophilic flavonoids on larvae are due to their high levels in birch buds and/or the inability of naïve neonates to glycosylate them, which we have shown to occur in fifth instars. To test the latter hypothesis, we investigated the biochemical transformation of bud flavonoids in first instar E. autumnata. We found that newly hatched larvae have the ability to glycosylate birch bud/leaf flavonoid aglycones into corresponding glycosides. Moreover, we suggest that glycosylation may depend upon the chemical character of the aglycone and is an important factor in the performance of first instars.     

Recognition of aphid parasitoids by honeydew-collecting ants: The role of cuticular lipids in a chemical mimicry system

The aphidiid waspLysiphlebus cardui parasitizes in ant-attendedAphis fabae cirsiiacanthoidis colonies without causing aggressive behavior in the antLasius niger. By contrast,Trioxys angelicae, another aphidiid parasitoid of aphids, is rapidly recognized and vigorously attacked by the ants.L. niger workers also responded differently to dead individuals ofL. cardui andT. angelicae. DeadL. cardui parasitoids were often ignored when encountered byL. niger, whereas deadT. angelicae individuals were immediately grasped by ants that discovered them. However, hexane-washed parasitoids caused a similar reaction pattern in the ants, in that both aphidiid species were tolerated in the aphid colony. Lure experiments demonstrated that chemical stimuli on the cuticle are major cues for the ants to distinguish between the parasitoids. The hexane extract ofL. cardui transferred to washed individuals ofT. angelicae resulted in ant responses characteristic towardsL. cardui, andL. niger workers displayed the typical removal pattern they normally showed towardsT. angelicae whenT. angelicae extract was applied toL. cardui individuals. Both parasitoid species treated with the hexane extract ofA. fabae cirsiiacanthoidis were similarily treated by the ants as were aphid control individuals. The suggestion that the aphidiid waspL. cardui uses chemical mimicry is discussed.     

Trade-Off Between Chemical and Biotic Antiherbivore Defense in the South East Asian Plant Genus Macaranga

The plant genus Macaranga is known for its manifold mutualistic associations with ants. The plants provide food for the ants and in turn get protection from herbivores. Depending on the strength of the plant–ant interaction, the plant's investment in ants and the biotic defense derived from them is more or less effective. We conducted a comparative study on tannin content in 12 Macaranga species that were selected based on their associations with ants (three nonmyrmecophytes and nine myrmecophytes, three of which start their ontogeny as nonmyrmecophytes). Different developmental stages were investigated in three Macaranga species. Extracts of every individual plant analyzed for tannins were also tested for their effects on larval growth employing larvae of the common cutworm (Spodoptera littoralis). The studied Macaranga species differed significantly in their tannin contents as well as in the effects of their leaf extracts on the growth of S. littoralis larvae. A correlation analysis shows a connection between tannin contents and larval growth. High tannin contents and, thus more effective chemical defense, were observed in nonmyrmecophytic Macaranga species associated only facultatively with ants as compared to obligate myrmecophytes. Our study supports the hypothesis of a trade-off between chemical and biotic defense in the genus Macaranga.     

Composition of larval secretion ofChrysomela lapponica (Coleoptera,Chrysomelidae) and its dependence on host plant

The defensive secretion ofChrysomela lapponica larvae, which is produced by nine pairs of exocrine dorsal glands, has been chemically analyzed. TheC. lapponica larvae were kept in the laboratory on leaves of either birch (Betula pendula), alder (Alnus glutinosa), or willow (Salix fragilis). Larvae developed normally on birch and willow, whereas those on alder died within a few days. GC-MS analyses of the secretion of larvae on birch and willow revealed that the composition of this secretion differs distinctly from the known ones of several otherChrysomela species feeding exclusively on Salicaceae. In the exocrine secretion of larvae on birch, 69 compounds were identified, which included the main components isobutyric acid, 2-methylbutyric acid, and esters of the two. Several of the esters have not been reported previously from nature. The alcoholic components of the esters may be hydrolysis products ofBetula glycosides. Most components of the secretion of larvae feeding on birch were also found in the secretion of larvae feeding on willow. In addition, major amounts of benzoic acid and salicylalcohol were present in the secretion of the larvae feeding on willow.C. lapponica obviously acquires salicylalcohol by hydrolysis of salicin from willow leaves. However, in contrast to otherChrysomela species,C. lapponica larvae oxidize only traces of salicylalcohol to salicylaldehyde. The repellent activity of single authentic compounds of the secretion of larvae feeding on birch and willow, respectively, was tested in laboratory bioassays with ants (Myrmica sabuleti). Biosynthetic pathways to some identified compounds are suggested and discussed under evolutionary and functional aspects.     

From Terpenoids to Aliphatic Acids: Further Evidence for Late-Instar Switch in Osmeterial Defense as a Characteristic Trait of Swallowtail Butterflies in the Tribe Papilionini

We compared the chemical compositions of the osmeterial secretions of fourth and fifth (last) instars of eight swallowtail species of the tribe Papilionini. Four species (Papilio demoleus, P. polytes, P. paris, and P. macilentus) are Asian Rutaceae-feeding swallowtails. The other four (Chilasa epicydes, C. agestor, P. troilus, and P. glaucus) represent more distant clades within the Papilionini and species with larval hosts in other plant families. We conducted a quantitative analysis for six species, but only qualitative analysis for P. glaucus and C. agestor. In all eight species, regardless of larval host plant, secretions of the fourth instar principally consisted of mono- and sesquiterpene hydrocarbons, whereas those of the fifth instar comprised aliphatic acids and their esters. Consistent with earlier findings, our results suggest that this “heterogeneous” pattern of osmeterial chemistry, not seen in other tribes, may characterize the Papilionini as a whole. Unlike those of most Papilio species, the fourth and fifth instars of Chilasa species resemble each other in body coloration. Thus, the heterogeneous osmeterial pattern is not necessarily associated with color change in papilionid larvae. The major terpenoids identified in fourth instar larval secretions from the six species were α-pinene, sabinene, β-myrcene, limonene, β-phellandrene, (Z)-β-ocimene, (E)-β-ocimene, p-mentha-1,4(8)-diene, β-elemene, β-caryophyllene, (E)-β-farnesene, (3Z,6E)-α-farnesene, (Z)-α-bisabolene, germacrene-A, (E)-α-bisabolene, and germacrene-B. The profiles for individual species differed both qualitatively and quantitatively from one another, and certain species also secreted methyl 3-hydroxy-n-butyrate and oxygenated sesquiterpenes in relatively large proportions. Secretions from fifth instars were composed of varying proportions of isobutyric, 2-methylbutyric, and acetic acids, and methyl and ethyl (minor) esters of both isobutyric and 2-methylbutyric acids. The heterogeneity of osmeterial chemistry in the tribe Papilionini may represent fine-tuning of chemical defense in response to shifting predation pressures as the larvae age and grow.     

Larval Beetles Form a Defense from Recycled Host-Plant Chemicals Discharged as Fecal Wastes

Larvae of the leaf-feeding beetles Neolema sexpunctata and Lema trilinea carry feces on their backs that form shields. We used the generalist predatory ant, Formica subsericea, in a bioassay to determine whether shields were a physical barrier or functioned as a chemical defense. Fecal shields protected both species against ant attack. Larvae of both species reared on lettuce produced fecal shields that failed to deter ants. Commelina communis, N. sexpunctata's host, lacks noxious secondary compounds but is rich in phytol and fatty acids, metabolites of which become incorporated into the fecal defense. In contrast, the host plant of L. trilinea, Solanum dulcamara, contains steroidal glycoalkaloids and saponins, whose partially deglycosylated metabolites, together with fatty acids, appear in Lema feces. Both beetle species make modifications to host-derived precursors before incorporating the metabolites into shields. Synthetic chemicals identified as shield metabolites were deterrent when applied to baits. This study provides experimental evidence that herbivorous beetles form a chemical defense by the elimination of both primary and secondary host-derived compounds. The use of host-derived compounds in waste-based defenses may be a more widely employed strategy than was hitherto recognized, especially in instances where host plants lack elaborate secondary compounds.     

Chemistry and functions of exocrine secretions of the antsTapinoma melanocephalum and T. erraticum

Volatile constituents produced by ant workers belonging to the speciesTapinoma melanocephalum andT. erraticum have been analyzed by gas chromatography-mass spectrometry. The pygidial (=anal) gland secretion ofT. melanocephalum is fortified with 6-methyl-5-hepten-2-one and actinidine (the mass spectrum of which is corrected in this paper). An unidentified compound was detected in cephalic extracts. The pygidial gland secretion ofT. erraticum was also dominated by 6-methyl-5-hepten-2-one, in addition to two isomers of iridodial, and iridomyrmecin. The sternal glands contained iridodial and C₁₅-C₂₀ hydrocarbons. Workers ofT. melanocephalum effectively utilize their pygidial gland secretions as an alarm-defense system during aggressive encounters with workers ofSolenopsis geminata. 6-Methyl-5-hepten-2-one is active as a releaser of alarm behavior, and actinidine is repellent to workers ofT. melanocephalum. Cephalic extracts possessed attractant and arrestant properties for workers of this species.     

Harvester Ants Utilize Cuticular Hydrocarbons in Nestmate Recognition

Cuticular hydrocarbons appear to play a role in ant nestmate recognition, but few studies have tested this hypothesis experimentally with purified hydrocarbon extracts. We exposed captive colonies of the harvester ant Pogonomyrmex barbatus to small glass blocks coated with whole cuticular lipid extracts and the purified hydrocarbon portion of extracts from nestmate and nonnestmate workers. As an estimate of agonistic behavior, we measured the proportion of ants in contact with blocks that flared their mandibles. Blocks coated with cuticular extracts from nonnestmates were contacted by more workers in one of two experiments and elicited higher levels of aggression in both experiments than blocks bearing extracts from nestmates. The cuticular hydrocarbon fraction of extracts alone was sufficient to elicit agonistic behavior toward nonnestmates. The results demonstrate that harvester ants can perceive differences in cuticular hydrocarbon composition, and can use those differences in nestmate recognition.     

Reaction of Mutualistic and Granivorous Ants to Ulex Elaiosome Chemicals

It has been proposed that chemicals on plant elaiosomes aid seed detection by seed-dispersing ants. We hypothesized that the chemical interaction between ants and elaiosomes is more intimate than a generic attraction, and that elaiosome chemicals will attract mutualistic but not granivorous ant species. We investigated this by using two gorse species, Ulex minor and U. europaeus, and two associated ant species from European heathlands, the mutualist Myrmica ruginodis and the granivore Tetramorium caespitum. Behavioral studies were conducted with laboratory nests and foraging arenas. Both ants will take Ulex seeds, but while M. ruginodis showed increased antennation toward ether extracts of elaiosome surface chemicals compared with controls, T. caespitum showed no response. Elaiosome extracts were separated into seven lipid fractions. M. ruginodis showed increased antennation only toward the diglyceride fractions of both Ulex species, whereas T. caespitum showed no consistent reaction. This indicates that M. ruginodis can detect the elaiosome by responding to its surface chemicals, but T. caespitum is unresponsive to these chemicals. Responses to surface chemicals could increase the rate of seed detection in the field, and so these results suggest that Ulex elaiosomes produce chemicals that facilitate attraction of mutualistic rather than granivorous ant species. This could reduce seed predation and increase Ulex fitness.