5.Lam, K; Tsang, M; Labrie, A; Gries, R; Gries, G. (2010) Semiochemical-Mediated Oviposition Avoidance by Female House Flies, Musca domestica, on Animal Feces Colonized with Harmful Fungi.Journal of Chemical Ecology 36: 141-147 Semiochemical-Mediated Oviposition Avoidance by Female House Flies, Musca domestica, on Animal Feces Colonized with Harmful Fungi
House flies; Musca domestica; Phoma spp.; Rhizopus spp.; Fungi; Animal feces; Resource competition; Oviposition; Semiochemicals; Dimethyl trisulfide; 2-Phenylethanol
House flies, Musca domestica, utilize ephemeral resources such as animal feces for oviposition and development of larval offspring, but they face competition with fungi that colonize the same resource. We predicted that house flies avoid oviposition on feces well-colonized with fungi, thereby reducing fungal competition for larval offspring. Working with fungal isolates from chicken feces, we have previously shown that prior establishment of Phoma spp., Fusarium spp., or Rhizopus spp. on feces significantly reduced oviposition by house flies. Here, we report that, in the headspace volatiles of these three fungal genera, five compounds (dimethyl trisulfide, an unknown, 2-phenylethanol, citronellal, norphytone) elicit responses from house fly antennae. In behavioral bioassays, dimethyl trisulfide and 2-phenylethanol significantly reduced oviposition by house flies. We conclude that fungus-derived volatiles serve as semiochemical cues that help house flies avoid resources colonized with fungal competitors for the development of larval offspring. DOI
3.Lam, K; Geisreiter, C; Gries, G. (2009) Ovipositing female house flies provision offspring larvae with bacterial food.Entomologia Experimentalis et Applicata 133: 292-295 Ovipositing female house flies provision offspring larvae with bacterial food
DROSOPHILA; DIPTERA; CULICIDAE; BEHAVIOR
Symbiotic bacteria on house fly eggs, Musca domestica L. (Diptera: Muscidae), provide ovipositional cues for conspecific female flies and curtail the growth of fungi that compete with fly larval offspring for resources. Because bacteria are also essential dietary constituents for developing larvae, we tested the hypothesis that egg-derived bacteria support development of larvae to adults. From house fly eggs, we isolated and identified 12 strains of bacteria, eight and four of which were previously shown to induce and inhibit oviposition, respectively. When larvae were provisioned with a total dose of 106-107 colony-forming units of bacteria from either the oviposition-inducing or inhibiting group, or from both groups together, significantly more larvae completed development. Thus, egg-associated bacteria could be a fail-safe mechanism that ensures a bacterial food supply for larval offspring, particularly if the resource selected by parent females is poor in bacterial food. DOI
2.Lam, K; Thu, K; Tsang, M; Moore, M; Gries, G. (2009) Bacteria on housefly eggs, Musca domestica, suppress fungal growth in chicken manure through nutrient depletion or antifungal metabolites.Naturwissenschaften 96: 1127-1132 Bacteria on housefly eggs, Musca domestica, suppress fungal growth in chicken manure through nutrient depletion or antifungal metabolites
DROSOPHILA; LARVAE; COMPETITION; SYMBIONTS; DIPTERA; FLIES; PLANT; FLY
Female houseflies, Musca domestica (Diptera: Muscidae), lay their eggs in ephemeral resources such as animal manure. Hatching larvae compete for essential nutrients with fungi that also colonize such resources. Both the well-known antagonistic relationship between bacteria and fungi and the consistent presence of the bacterium Klebsiella oxytoca on housefly eggs led us to hypothesize (1) that K. oxytoca, and possibly other bacteria on housefly eggs, help curtail the growth of fungal resource competitors and (2) that such fungi indeed adversely affect the development of housefly larvae. Bacteria washed from housefly eggs significantly reduced the growth of fungi in chicken manure. Nineteen bacterial strains and ten fungal strains were isolated from housefly eggs or chicken manure, respectively. Co-culturing each of all the possible bacterium-fungus pairs revealed that the bacteria as a group, but no single bacterium, significantly suppressed the growth of all fungal strains tested. The bacteria's adverse effect on fungi is due to resource nutrient depletion and/or the release of antifungal chemicals. Well-established fungi in resources significantly reduced the number of larval offspring that completed development to adult flies. DOI
1.Lam, K; Babor, D; Duthie, B; Babor, EM; Moore, M; Gries, G. (2007) Proliferating bacterial symbionts on house fly eggs affect oviposition behaviour of adult flies.Animal Behaviour 74: 81-92 Proliferating bacterial symbionts on house fly eggs affect oviposition behaviour of adult flies
bacterial symbiont; communication ecology; house fly; microhabitat management; Musca domestica; reproductive strategy; signalling
Animals commonly leave scent messages by depositing pheromones, faeces, or urine. The intensity of a chemical message may fade over time, but the 'intention' remains the same. We argue that house flies, Musca domestica (Diptera: Muscidae), require a message with evolving (sensu changing over time) information content. Gravid females reportedly deploy a pheromone that induces concerted oviposition so that many even-aged larvae ameliorate the resource, such as animal manure. However, continued oviposition by late-arriving females may result in age disparity and cannibalism of larval offspring. Thus, we predicted that house flies have a type of cue that evolves from oviposition induction to inhibition some time after eggs are deposited on a resource. Here we show (1) the existence of such evolving ovipositional cues, (2) the adverse fitness consequences that accrue from ignoring the inhibitory cues and (3) the mechanism by which these cues evolve. The evolving cues depend upon a key bacterial strain, Klebsiella oxytoca, which originates with female M. domestica and which proliferates over time on the surface of deposited eggs. At a threshold density of this strain, further oviposition is inhibited. By deploying such evolving cues, female M. domestica can visit an oviposition site just once and deposit cues that will mediate immediate oviposition induction followed by delayed inhibition, thereby ensuring conditions conducive for offspring development. (C) 2007 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved. DOI
