RESUMO
In myrmecophilous organisms, which live in symbiosis with ants, cuticular hydrocarbons (CHCs) play a pivotal role in interspecific communication and defense against chemical-oriented predators. Although these interactions form complex information webs, little is known about the influence of biotic environmental factors on the CHC profiles of myrmecophiles. Here, we analyzed the effect of different host plants and tending ants on the larval CHC profile of Synargis calyce (Lepidoptera: Riodinidae), a polyphagous species with facultative myrmecophily. Groups of caterpillars were fed individually with three host plant species (without tending ants), and with two tending ant species. Through gas chromatography analysis, we compared the cuticular profiles of treatments and found a high similarity between plants and caterpillars (65-82%), but a low similarity between caterpillars and their tending ants (30 - 25%). Cluster analysis showed that caterpillars, ants, and plants form distinct groups, indicating that S. calyce caterpillars have their own chemical profile. These results are similar to those observed for Lycaenidae caterpillars indicating that there is functional convergence in the chemical strategies used by myrmecophilous caterpillar species with similar ecology. Also, the results suggest that the cuticular compounds of S. calyce are primarily influenced by their host plants rather than their tending ants. Thus, we propose that these caterpillars present a trade-off between camouflage and directly informing their presence to ants, maintaining their unique chemical profile, though slightly affected by biotic environmental factors.
Assuntos
Formigas , Hidrocarbonetos , Larva , Animais , Formigas/fisiologia , Formigas/química , Formigas/metabolismo , Hidrocarbonetos/metabolismo , Hidrocarbonetos/química , Hidrocarbonetos/análise , Larva/fisiologia , Larva/química , Simbiose , Borboletas/fisiologia , Borboletas/químicaRESUMO
Predatory behavior of Pseudodorus clavatus (Diptera, Syrphidae) on aphids tended by ants. In this study, we examined the interactions between myrmecophilous aphids, their ant-guards and a predatory syrphid species, Pseudodorus clavatus (F.). Larvae of this predator were found in the colonies of three aphid species: Aphis gossypii, A. spiraecola and Toxoptera sp., which were tended by eight ant species, especially Camponotus. Hoverfly larvae managed to infiltrate the aphid colonies and consume nymphs. Predator larvae exhibited inconspicuous movements and were not detected by ants which were commonly observed touching and antennating the larvae they come into contact. These results suggest that behavioral and chemical cues are involved in the infiltration and on the successful predation of syrphids upon aphids.
RESUMO
We evaluated the hypothesis that the abundance and species distribution of two different kinds of myrmecophilous plants is influenced differently by the ant diversity and abundance. In eight different natural forests in Venezuela we estimated the species richness and abundance of plants, ants on the soil and on the canopy, the leaf damage of plants and soil nutrients. The main results of the study show that plants with domatia (PD) and plants with extrafloral nectaries (PEFN) have different relationships with ants and suffer from different ecological constraints. PD attract a more specific group of ants than PEFN. Our results are consistent with the hypothesis that domatia are adaptations that help plants to increase rare nutrient uptake rather than for herbivore defense. We found that PEFN attract a larger variety of ant species than PD, and ant abundance seems to limit the ecological range of PEFN. The attraction of ants as a mechanism to reduce herbivory, as done by PEFN, does not seem to be superior to alternative anti-herbivore mechanisms used by other plants. Contrary to many former studies, we found that ants are generally more diverse on the soil compared to canopies.
Avaliou-se a hipótese de que a distribuição da abundância e o número de espécie de dois tipos diferentes de plantas mirmecófilas são influenciadas diferentemente pela diversidade e pela abundância de formigas. Em oito florestas naturais diferentes na Venezuela nós estimamos a riqueza de espécies e a abundância de plantas, de formigas no solo e no dossel, os danos às folhas e os nutrientes do solo. Os resultados mostram que as plantas com domácias para alojar formigas e plantas com nectários extraflorais (PEFN) têm relacionamentos diferentes com formigas e sofrem confinamentos ecológicos diferentes. As plantas com domácias atraem um grupo mais específico de formigas do que as PEFN. Os resultados são consistentes com a hipótese de que as domácias são adaptações que ajudam a planta a aumentar o acesso a nutrientes escassos para a defesa de herbívoros. PEFN atraem uma variedade maior da espécie de formigas do que as plantas com domácias, e a abundância de formigas parece limitar a escala ecológica de PEFN. A atração das formigas como mecanismo para reduzir a herbivoria, como feito por PEFN, não parece ser superior aos mecanismos alternativos de prevenção de herbivoria usados por outras plantas. Contrário a muitos estudos anteriores, as formigas mostraram-se geralmente mais diversas no solo comparado ao dossel.
Assuntos
Animais , Formigas , Ecossistema , Árvores , VenezuelaRESUMO
A new myrmecophilous silverfish (Zygentoma: Nicoletiidae: Subnicoletiinae) from Rio de Janeiro, Brazil, found living in fire ant (Solenopsis saevissima, Formicidae: Myrmicinae) nests is described: Allotrichotriura saevissima gen. nov. sp. nov. is compared with the other genera and subgenera known in the subfamily. The main diagnostic features would include the combination of body shape, body and head setation, morphology of praetarsus, and number of abdominal stylets and vesicles. Although further quests were attempted at the type-locality, only the original described material, exclusively composed of females, remains known.
Descreve-se um novo Zygentoma (Nicoletiidae: Subnicoletiinae), mirmecófilo da formiga lava-pés Solenopsis saevissima (Formicidae: Myrmicinae) no Estado do Rio de Janeiro, Brasil: Allotrichotriura saevissima gen. nov. sp. nov. que é comparado com os géneros e subgéneros conhecidos na subfamília. As principais características diagnósticas respeitam a combinação da forma do corpo, quetotaxia cefálica e do corpo, morfologia do prétarso e número de estilos e vesículas abdominais. Embora prospecções recentes tenham sido levadas a cabo na localidade típica, apenas se conhece a amostra original, que integra exclusivamente fêmeas.
RESUMO
A new myrmecophilous silverfish (Zygentoma: Nicoletiidae: Subnicoletiinae) from Rio de Janeiro, Brazil, found living in fire ant (Solenopsis saevissima, Formicidae: Myrmicinae) nests is described: Allotrichotriura saevissima gen. nov. sp. nov. is compared with the other genera and subgenera known in the subfamily. The main diagnostic features would include the combination of body shape, body and head setation, morphology of praetarsus, and number of abdominal stylets and vesicles. Although further quests were attempted at the type-locality, only the original described material, exclusively composed of females, remains known.
Descreve-se um novo Zygentoma (Nicoletiidae: Subnicoletiinae), mirmecófilo da formiga lava-pés Solenopsis saevissima (Formicidae: Myrmicinae) no Estado do Rio de Janeiro, Brasil: Allotrichotriura saevissima gen. nov. sp. nov. que é comparado com os géneros e subgéneros conhecidos na subfamília. As principais características diagnósticas respeitam a combinação da forma do corpo, quetotaxia cefálica e do corpo, morfologia do prétarso e número de estilos e vesículas abdominais. Embora prospecções recentes tenham sido levadas a cabo na localidade típica, apenas se conhece a amostra original, que integra exclusivamente fêmeas.