Papers by Robert Vander Meer
Research Square (Research Square), Jun 6, 2022
Ants use a variety of semiochemicals for essential activities and have been a source for many nov... more Ants use a variety of semiochemicals for essential activities and have been a source for many novel natural products. While ant taxa produce a wide variety of chemicals, the chemistry and ecology of male ants has remained understudied. Tyramides are a class of compound that have been found only in males of the Myrmicinae ant subfamily. Tyramides found in the fire ant Solenopsis invicta are transferred to gynes during mating where they are converted to tyramine, leading to rapid reproductive development. To further understand the evolution of tyramide production in male ants, we determined the tyramide composition in males of 15 fungus-growing ant species (Formicidae: Myrmicinae: Attini: Attina) and a Megalomyrmex species (Formicidae: Myrmicinae: Solenopsidini). Thirteen tyramides were identified, four for the first time in natural sources, and their percent composition was mapped to the fungus-growing ant phylogeny. This research contributes to an understanding of the evolution of male-produced tyramides.
Tetrahedron, 1994
Abstract An effective and practical procedure has been developed that allows the assignment of th... more Abstract An effective and practical procedure has been developed that allows the assignment of the absolute configuration of solenopsins from diverse origins us
Journal of Chemical Ecology, May 1, 2016
The Noctuidae are one of the most speciose moth families and include the genera Helicoverpa and H... more The Noctuidae are one of the most speciose moth families and include the genera Helicoverpa and Heliothis. Females use (Z)-11-hexadecenal as the major component of their sex pheromones except for Helicoverpa assulta and Helicoverpa gelotopoeon, both of which utilize (Z)-9-hexadecenal. The minor compounds found in heliothine sex pheromone glands vary with species, but hexadecanal has been found in the pheromone gland of almost all heliothine females so far investigated. In this study, we found a large amount (0.5-1.5 ÎĽg) of hexadecanal and octadecanal on the legs of males of four heliothine species, Helicoverpa zea, Helicoverpa armigera, H. assulta, and Heliothis virescens. The hexadecanal was found on and released from the tarsi, and was in much lower levels or not detected on the remaining parts of the leg (tibia, femur, trochanter, and coxa). Lower amounts (0.05-0.5 ÎĽg) of hexadecanal were found on female tarsi. This is the first known sex pheromone compound to be identified from the legs of nocturnal moths. Large amounts of butyrate esters (about 16 ÎĽg) also were found on tarsi of males with lower amounts on female tarsi. Males deposited the butyrate esters while walking on a glass surface. Decapitation did not reduce the levels of hexadecanal on the tarsi of H. zea males, indicating that hexadecanal production is not under the same neuroendocrine regulation system as the production of female sex pheromone. Based on electroantennogram studies, female antennae had a relatively high response to hexadecanal compared to male antennae. We consider the possible role of aldehydes and butyrate esters as courtship signals in heliothine moths.
Genetics, 2006
Males in polygyne populations of Solenopsis invicta are primarily sterile diploids and thought to... more Males in polygyne populations of Solenopsis invicta are primarily sterile diploids and thought to not express the Gp-9 gene coding for a pheromone-binding protein affecting complex social behavior. We examined an aspect of the breeding system hitherto not considered—male Gp-9 genotypes in relation to sperm stored in queens. Four sites with varying frequencies of sympatric monogyne and polygyne colonies were sampled, including sexuals, workers, and broods from four colonies. Most queens were heterozygotes storing B sperm. Although predicted to be common, only 14 of 504 males were B or BB genotypes, suggesting strong selection. Increased frequency of polygyne colonies at each site paralleled increases in queens with b sperm (1.9–32.8%) and of noninseminated queens. The presence of both B and b sperm in 1.9–18.9% of queens, genotype profiles of colonies, and genotypes of offspring from individual queens suggest some frequency of multiple mating. The bb genotype, rather than an obligate...
Studies of alkaloids isolated from the skins of neotropical poison frogs (Dendrobatidae) have led... more Studies of alkaloids isolated from the skins of neotropical poison frogs (Dendrobatidae) have led to the discovery of nearly 500 compounds, representing over 20 alkaloid structural classes. The skin alkaloids of dendrobatids, are acquired from the ants mites, and other leaf-litter arthropods that these frogs eat, generally are believed to deter vertebrate predators, e.g., snakes and birds. The biological activities of alkaloids from dendrobatids and other anurans, however, are known primarily from neuromuscular preparations designed to uncover pharmacological modes of action. We test the hypotheses that: 1) poison dart frog skin alkaloids, acquired in part from ants, are an effective deterrent to ant predation and 2) poison dart frog skin alkaloids deter predatory ants even if the alkaloids are derived from that predatory ant. To do this we developed a very sensitive contact bioassay using Solenopsis invicta as the test ant. We challenged the ants in this bioassay with 20 alkaloids (12 structural classes) identified from dendrobatids or other anurans. Results clearly demonstrate that not all frog alkaloids deter fire ants at concentrations that would be found in nature, but others were highly active. We also found that the ant, Solenopsis geminata, originates in Central America and is sympatric with a poison dart frog, Oophaga pumilio, that sequesters the main piperidine alkaloid produced by S. geminata. The contact bioassay showed that this piperidine alkaloid was not effective against S. invicta. How this impacts the relationship between the ant and poison dart frog will be discussed.
Ants use a variety of semiochemicals for essential activities and have been a source for many nov... more Ants use a variety of semiochemicals for essential activities and have been a source for many novel natural products. While ant taxa produce a wide variety of chemicals, the chemistry and ecology of male ants has remained understudied. Tyramides are a class of compound that have been found only in males of the Myrmicinae ant subfamily. Tyramides found in the fire ant Solenopsis invicta are transferred to gynes during mating where they are converted to tyramine, leading to rapid reproductive development. To further understand the evolution of tyramide production in male ants, we determined the tyramide composition in males of 15 fungus-growing ant species (Formicidae: Myrmicinae: Attini: Attina) and a Megalomyrmex species (Formicidae: Myrmicinae: Solenopsidini). Thirteen tyramides were identified, four for the first time in natural sources, and their percent composition was mapped to the fungus-growing ant phylogeny. This research contributes to an understanding of the evolution of m...
Naturwissenschaften
In honeybees, workers under queenless condition compete for reproduction and establish reproducti... more In honeybees, workers under queenless condition compete for reproduction and establish reproductive dominance hierarchy. Ovary activation is generally accompanied by the expression of queen-like pheromones. Biogenic amines (BAs), in particular dopamine, are believed to be involved in this process by regulating ovarian development. However, the role of BAs in establishing reproductive dominance or their effect on queen-like pheromone production was not investigated. Here, we explored the effect of octopamine (OA) and tyramine (TA) oral treatments on the propensity of treated bees to become reproductively dominant and produce queen-like pheromones in Dufour’s and mandibular glands. One bee in a pair was treated with either OA or TA while the other was fed sugar solution. TA was found to enhance ovary development and the production of esters in the Dufour’s gland and 9HDA (queen component) in the mandibular glands, thus facilitating worker reproductive dominance. OA, on the other hand,...
…, 2009
The preference of red imported fire ants, Solenopsis invicta, for microencapsulated (MC) pyriprox... more The preference of red imported fire ants, Solenopsis invicta, for microencapsulated (MC) pyriproxifen based corn grit baits (P-bait) was conducted in laboratory and field conditions. A positive correlation between the microencapsulation rate and water tolerance ability of P-bait was observed. A 20% increment of water tolerance ability of P-baits was observed when P-baits were microencapsulated with 5% poly-ε-caprolactone. The microencapsulated and wet P-baits were less preferred than normal P-baits by the fire ants either in laboratory or field conditions. Based upon these results, poly-ε-caprolactone coated fire ant baits cannot be considered as perfect fire ant baits.
…, 2009
The preference of red imported fire ants, Solenopsis invicta, for microencapsulated (MC) pyriprox... more The preference of red imported fire ants, Solenopsis invicta, for microencapsulated (MC) pyriproxifen based corn grit baits (P-bait) was conducted in laboratory and field conditions. A positive correlation between the microencapsulation rate and water tolerance ability of P-bait was observed. A 20% increment of water tolerance ability of P-baits was observed when P-baits were microencapsulated with 5% poly-ε-caprolactone. The microencapsulated and wet P-baits were less preferred than normal P-baits by the fire ants either in laboratory or field conditions. Based upon these results, poly-ε-caprolactone coated fire ant baits cannot be considered as perfect fire ant baits.
Neuropeptides control various physiological functions and constitute more than 90% of insect horm... more Neuropeptides control various physiological functions and constitute more than 90% of insect hormones.
Journal of Invertebrate Pathology, 2007
Studies were conducted to examine the phenology, geographic distribution, and host specificity of... more Studies were conducted to examine the phenology, geographic distribution, and host specificity of the Solenopsis invicta virus-1 (SINV-1). Two genotypes examined, SINV-1 and-1A, exhibited similar seasonal prevalence patterns. Infection rates among colonies of S. invicta in Gainesville, Florida, were lowest from early winter (December) to early spring (April) increasing rapidly in late spring (May) and remaining high through August before declining again in the fall (September/October). Correlation analysis revealed a significant relationship between mean monthly temperature and SINV-1 (p < 0.0005, r = 0.82) and SINV-1A (p < 0.0001, r = 0.86) infection rates in S. invicta colonies. SINV-1 was widely distributed among S. invicta populations. The virus was detected in S. invicta from Argentina and from all U.S. states examined, with the exception of New Mexico. SINV-1 and-1A were also detected in other Solenopsis species. SINV-1 was detected in Solenopsis richteri and the S. invicta/richteri hybrid collected from northern Alabama and Solenopsis geminata from Florida. SINV-1A was detected in S. geminata and Solenopsis carolinensis in Florida and the S. invicta/richteri hybrid in Alabama. Of the 1989 arthropods collected from 6 pitfall trap experiments from Gainesville and Williston, Florida, none except S. invicta tested positive for SINV-1 or SINV-1A. SINV-1 did not appear to infect or replicate within Sf9 or Dm-2 cells in vitro. The number of SINV-1 genome copies did not significantly increase over the course of the experiment, nor were any cytopathic effects observed. Phylogenetic analyses of SINV-1/-1A nucleotide sequences indicated significant divergence between viruses collected from Argentina and the U.S.
Animal Behaviour, 2002
A new colony of the slave-making ant Polyergus breviceps is initiated when a newly mated gyne inv... more A new colony of the slave-making ant Polyergus breviceps is initiated when a newly mated gyne invades a host nest and kills the resident queen. This process seems to result in chemical camouflage of the invading gyne and allows her to usurp the position of colony reproductive. Young, recently mated Formica gynes, however, are not attacked. To determine whether worker and/or immature presence is the basis for aggression, we placed eggs, larvae, pupae and workers from mature F. gnava queens with newly mated F. gnava queens and observed the responses of introduced P. breviceps queens. Because no newly mated gyne was attacked, we tested newly mated F. gnava queens (1) once they had produced eggs, (2) when the offspring reached the larval, pupal and callow stages of development, and (3) every 2 weeks until aggression ensued. Eventually all F. gnava queens were attacked but only 29 weeks after having mated. Thus, although offspring are the ultimate benefit from attacking an established F. gnava queen, P. breviceps queens detect mature queens using another time-dependent feature that is reliably indicative of reproductive status. The similarity of host queen hydrocarbon profiles, often correlated with reproductive status in other ant species, suggests that other compounds reflect queen fecundity and produce a kairomonal effect, or that another cue signals host queen and colony suitability. Our findings indicate P. breviceps gynes have evolved to respond aggressively to a host gyne cue that appears long after mating, preventing attacks on gynes without the workers necessary for colony founding.
New Scientist, 2006
Aggressive and venomous, red fire ants have invaded 14 US states and reached Puerto Rico, attacki... more Aggressive and venomous, red fire ants have invaded 14 US states and reached Puerto Rico, attacking people, wildlife and electrical systems. In an interview, Robert Vander Meer talks about the scale of the infestation and ways to fight back against the US's most invasive pest.
ABSTRACT Alarm pheromones of social insects are best known for their role in the defence and main... more ABSTRACT Alarm pheromones of social insects are best known for their role in the defence and maintenance of colony integrity. Previous studies with the fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) demonstrate that the mandibular glands of workers (sterile females) and male and female sexuals produce an alarm pheromone, 2-ethyl-3,6-dimethylpyrazine. The function of alarm pheromones in worker ants is well understood and divergent from the function of these compounds in the winged sexual forms. The present study quantifies the amount of pyrazine in the mandibular glands from male and female alate sexuals, as well as queens. Pyrazine production in female alates starts in the late pupal stage and increases until they reach mating flight-ready maturity; however, after mating flight participation, the pyrazine level declines by &gt;50%. Interestingly, mature male alates lose &gt;85% of their mandibular gland pyrazine during mating flight activity. The results of the present study indicate that male and female sexuals use mandibular gland secretions for mating flight initiation and during mating flights. Furthermore, the ontogeny of mandibular gland products (pyrazine as the marker) from newly-mated queens to mature colony queens shows a more than two-fold increase in the amount of pyrazine by 6 months after mating. However, this is followed by a decline to trace amounts in mature colony queens (&gt;2 years old), suggesting a function for mandibular gland products during colony development. Multifunctional use of social insect pheromones is well documented and data are reported in the present study suggesting new roles for mandibular gland products in fire ants.
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Papers by Robert Vander Meer