Martelli, M.G*., M.M. Ward* and A.M. Fraser. 2004. Ant diversity sampling on the southern Cumberland Plateau: a comparison of litter sifting and pitfall trapping. Southeastern Naturalist 3:113-126.

ABSTRACT - We compared the efficacy and biases of pitfall trapping and Winkler extraction of sifted leaf litter for sampling the diversity of ground-dwelling ants in native oak-hickory hardwood forest and cultivated pine stands on the Cumberland Plateau in southern Tennessee. Samples yielded 2,635 individuals from 23 species, 17 genera, and 4 subfamilies. According to estimates of expected species richness, our sampling effort inventoried at least 82% of the ant fauna likely to be captured by these methods at a given site. Litter sifting yielded more individuals, more species and more occurrences of most species than did pitfall traps, but neither method captured all species. Most myrmicine and all ponerine species showed a significant bias toward capture by litter sifting, whereas pitfall traps tended to be more effective at capturing large-bodied Camponotus ants and species that forage outside of prime daylight hours, when litter samples were collected. Large pitfalls (75 mm diameter) caught more species and more individuals than small pitfalls (25 mm diameter). The preliminary survey indicated that a change from native hardwood to cultivated pine reduced species richness and altered the assemblage of ant species present, but did not alter community diversity or abundance of ants. Larger scale surveys involving commercial pine plantations are needed for more accurate assessments of how this type of land use change affects local ant diversity and ecosystem functioning.

Fraser, A.M., W.L. Mechaber and J.G. Hildebrand. 2003. Electroantennographic and behavioral responses of the sphinx moth Manduca sexta to host plant headspace volatiles. Journal of Chemical Ecology. 29:1813-1833.

ABSTRACT - Coupled gas chromatography with electroantennographic detection (GC-EAD) using antennae of adult female Manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: Solanaceae—Lycopersicon esculentum (tomato), Capiscum annuum (bell pepper), and Datura wrightii; and Martyniaceae—Proboscidea parviflora. Headspace volatiles were collected from undamaged foliage of potted, living plants. GC–EAD revealed 23 EAD-active compounds, of which 15 were identified by GC-mass spectrometry. Identified compounds included aliphatic, aromatic, and terpenoid compounds bearing a range of functional groups. Nine EAD-active compounds were common to all four host plant species: (Z)-3-hexenyl acetate, nonanal, decanal, phenylacetaldehyde, methyl salicylate, benzyl alcohol, geranyl acetone, (E)-nerolidol, and one unidentified compound. Behavioral responses of female moths to an eight-component synthetic blend of selected tomato headspace volatiles were tested in a laboratory wind tunnel. Females were attracted to the blend. A comparison of responses from antennae of males and females to bell pepper headspace volatiles revealed that males responded to the same suite of volatiles as females, except for (Z)-3-hexenyl benzoate. EAD responses of males also were lower for (Z)- and (E)-nerolidol and one unidentified compound. Electroantennogram EAG dose–response curves for the 15 identified EAD-active volatiles were recorded. At the higher test doses (10–100 µg), female antennae yielded larger EAG responses to terpenoids and to aliphatic and aromatic esters. Male antennae did respond to the higher doses of (Z)-3-hexenyl benzoate, indicating that they can detect this compound. On the basis of ubiquity of the EAD-active volatiles identified to date in host plant headspace collections, we suggest that M. sexta uses a suite of volatiles to locate and identify appropriate host plants.

Fraser, A.M., T. Tregenza, N. Wedell, M.A. Elgar and N.E. Pierce. 2002. Oviposition tests of ant preference in a myrmecophilous butterfly. Journal of Evolutionary Biology 15:861-870.

ABSTRACT - Butterflies in the family Lycaenidae that have obligate associations with ants frequently exhibit ant-dependent egg laying behavior. In a series of field and laboratory choice tests, we assessed oviposition preference of the Australian lycaenid Jalmenus evagoras in response to different species and populations of ants. Females discriminated between attendant and non-attendant ant species, between attendant ant species, and to some extent, between populations of a single ant species. When preferences were found, ovipositing butterflies preferred their locally predominant attendant ant species and geographically proximate attendant ant populations. A reciprocal choice test using adults from a generation of butterflies reared in the absence of ants indicated a genetic component to oviposition preference. Individual females were flexible with respect to oviposition site choice, often ovipositing on more than one treatment during a trial. Preferences arose from a hierarchical ranking of ant treatments. These results are discussed in terms of local adaptation and its possible significance in the diversification of ant-associated lycaenids.

Fraser, A.M., A.H. Axen and N.E. Pierce. 2001. Assessing the quality of different ant species as partners of a myrmecophilous butterfly. Oecologia 129:452-460. PDF

ABSTRACT - We assessed the quality of different ant species as partners of the facultatively myrmecophilous lycaenid butterfly Glaucopsyche lygdamus. We compared disappearance and parasitism rates of G. lygdamus larvae in the field, and development of non-feeding prepupae in the laboratory, when individuals were untended or tended by one of four ant species. Formica podzolica was the only ant species to provide a clear benefit to G. lygdamus, in the form of reduced larval parasitism relative to untended larvae. F. 'neogagates' (F. neogagates + F. lasioides) and Tapinoma sessile were essentially neutral partners, providing no significant cost or benefit for any of the parameters measured. Relative to untended individuals, association with F. obscuripes significantly increased larval disappearance and significantly decreased pupal mass. Thus, F. obscuripes may act as a parasite of the general association between G. lygdamus and ants under certain conditions. Ant species also differed in the persistence as tenders of G. lygdamus larvae once an interaction was established. Over the lifetime of a larva, F. podzolica and F. obscuripes usually remained as attendant ant species on plants over consecutive census dates, while F. 'neogagates' and T. sessile were frequently replaced, most commonly by F. obscuripes. It remains to be determined if disappearance and developmental outcomes reported here reflect true fitness costs (i.e. reduced survivorship and lower reproductive success) for G. lygdamus. The potential and limitations for specialization in association between G. lygdamus and high quality ant partners are discussed.

Eastwood, R. and A.M. Fraser. 1999. Associations between lycaenid butterflies and ants in Australia. Australian Journal of Ecology 24: 503-537.

ABSTRACT - A comprehensive and critical review of all available literature on associations between Australian lycaenid butterflies and ants was undertaken to establish an accurate database of the partners involved. Collections and observations of lycaenids and ants were used to augment this review, resulting in a significant number of newly documented association (and non-association) records. Twenty published records considered to be erroneous or doubtful are noted, with justifications given for their deletion from the association database. In total, 265 different associations between lycaenids and ants, plus 65 non-attendance records are documented for Australia. Nearly 80% of the lycaenid species in Australia, for which the early stages are known, are recorded associating with ants and half of these are obligately ant-associated. Patterns of association are examined from the perspective of both lycaenids and ants, with a focus on ant systematics and ecology. Lycaenids are recorded with five ant subfamilies, including the first record of an association with the Pseudomyrmecinae. The Dolichoderinae, and to some extent the Formicinae, have a disproportionately high percentage of genera that associate with lycaenid butterflies. All ant species that tend lycaenids spend at least some portion of their time foraging on vegetation to collect plant and insect nectar. There is a robust relationship between the competitive status of ants within a community, and their frequency and degree of association with lycaenids. Obligate ant-association is accompanied by a high degree of specificity for ant partner, but two notable exceptions, Ogyris aenone and O. amaryllis are discussed. Facultative myrmecophiles tend to associate with a broad range of ants, although interactions with ecologically dominant ants are less frequent than might be expected based on the abundance of dominant ant species in Australian communities.

Fraser, A.M. and T.B. Herman. 1993. Territorial and reproductive behaviour in a sympatric species complex of the neotropical damselfly Cora Selys (Zygoptera: Polythoridae). Odonatologica 22:411-429.

ABSTRACT - Sympatric populations of C. semiopaca, C. notoxantha and C. obscura were studied along a forest creek at El Rodeo Biological Reserve in Costa Rica. Territorial and reproductive behaviour of these 3 spp. are described and compared with C. marina, the only other Cora sp. studied to date. Males defended territories centered around rotting wood in the creek bed, used by females for oviposition. Territories of C. semiopaca, C. notoxantha and C. obscura were interspersed along the creek and were occupied simultaneously during the day. Extensive spatial and temporal overlap of resource use by the 3 spp. allowed for considerable interspecific interaction at the study site. Aggressive behaviour of males was similar among the 3 spp., with the exception of an escalated ascending spiral contest, observed only between C. semiopaca males. Reproductive behaviour was not elaborate; males did not perform courtship or postcopulatory site displays to females. Males of all spp. were rarely observed transferring sperm to their accessory genitalia, either while in tandem or while perched alone. The authors were unable to distinguish between females of the 3 Cora spp. at the study site. From records of marked individuals it also appears that semiopaca, notoxantha and obscura males could not distinguish between females of the 3 spp. since a high percentage (32%) of multiple mating females copulated with males of more than one Cora spp. Interspecific mating involved full (unshortened) copulation, often followed by oviposition. Recent sympatry of these 3 spp. is the most plausible explanation for an apparent lack of premating reproductive isolating mechanisms in these species. However, the possibility that these putative species are morphological variants of the same species is suggested.