Leaf-Cutter Ant Parasitoids: Current Knowledge
Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and of the habitats in those areas is a fundamental issue in designing urban parks. The phorid flies that parasitize ants use the host's body to complete their life cycle, and We evaluated the relationship between the abundance of each phorid. Habitat fragmentation can have a high impact on parasitoid–ant interactions. Phorid flies are among the most important groups of natural. Leafcutter ants are hosts of phorid parasitoids and represent a well-defined and specialised module . with which parasitoid species use each host in relation to host abundances; (iii) issues and opportunities. Journal of Animal sitism characteristics of two phorid fly species in relation to their host.
For example, a Evidently, parasitism rates not only change with seasons but also do across years. For example, for At. Rates of parasitism could also be related to the health status of the colonies, as discussed in Section 5. Host Sizes The parasitoid decision, about which host is good or not, should involve not only quality but also host size or amount of available food.
In general, the larger the host selected, the bigger the resulting adult phorid [ 925 ]. Host size is related to the amount of food available for the internal larvae to feed and be able to pupariate. Both, in Atta and Acromyrmex, several sizes are parasitized, but it is interesting to highlight that the ant size distribution available for parasitism does not differ statistically from that used for oviposition in Acromyrmex, though it does in Atta; for the latter the smallest, biggest, or both extremes of the ant size distribution are not used as hosts [ 932 ].
It is important to know the ant distribution available and that used by the phorids for two reasons: Therefore, community studies are necessary to make the best inferences and understand the community assembly rules involved for the species under study.
Sex Ratios Data recorded so far [ 92532 ] show that there is no sexual size dimorphism in adult flies nor in the size of the heads from which females and males emerge. This pattern holds for Acromyrmex as well as for Atta phorids. Possibly as a consequence of this, the sex ratio is near 1 or does not differ statistically from one in the many instances studied for phorids attacking leaf-cutter ants.
Parasitoids of the endangered leafcutter ant Atta robusta Borgmeier in urban and natural areas
This pattern is somehow unexpected because for many fire ant parasitoids females emerge from bigger head sizes whereas smaller heads produce males within a species [ 44 ]. The host size to adult fly size pattern is also very interesting because, on the one hand, the size of phorids is very different; for example, Eibesfeldtphora is double the size of Myrmosicarius, and two species of these genera attack the same size of the same host [ 32 ].
On the other hand, because of the great intraspecific plasticity of phorids, parasitoids coming from greater head sizes produce bigger phorids in comparison to those emerging from smaller ones [ 2532 ]. The Gestalt-Immunology Hypothesis A common pattern found in parasitoids attacking soil ants is that they parasitize ants from a few nests out of the total possible ones available in the same patch. Moreover, the same nests from which phorids emerged continue as such through time.
Similarly, the percentage of parasitism could vary enormously from one colony to the other close by [ 20 ]; Guillade unpublished. How do phorids assess which nest is good? If the health of a colony or its suitability as a good host is linked with a particular taste, then phorids could choose one nest but not another using sensorial cues.
It has been shown in ants the importance of a chemical signature, given by their cuticular hydrocarbons, which is used by nestmates to differentiate self from nonself [ 50 ]. This implies that the particular chemical can be sensed by other ants also.
We can extend this argument involving other organisms such as phorids. In fact, there is evidence from other systems that parasitoids can cue on the volatile compounds released by the plants due to having been fed by their herbivores [ 51 ]. Also, fire ant parasitoids use long-range olfactory cues to detect their hosts [ 42 ].
Healthy colonies with vigorous ants will better nourish the parasitoid larvae than unhealthy ones which will have an altered gestalt. As the cuticular hydrocarbons are nonvolatiles, this information should be gathered by a phorid at very close range, in fact, by touching it. This hypothesis can also help explain what is normally seen in fire ants, that is, where one colony is parasitized but not another one close by and surrounded by the same vegetation. In fact, cryptic sympatric species haplotypes are known of S.
Therefore, if there is a link between the cuticular hydrocarbons and the immunological status of the colonies, then a taste mechanism can be used to explain the parasitism rates discussed.Where Are the Ants Carrying All Those Leaves? - Deep Look
To my knowledge nothing is known about how the gestalt and immunological status of leaf-cutter ants or any other relate to each other and how these parameters could affect their relationships with natural enemies. De Souza et al. On the other hand, these host specificity ratios reflect data obtained from several regions and seasons. It will be interesting to analyze the web of interactions at a local scale and from a richness point of view.
Psyche: A Journal of Entomology
If it holds, that is, finding more parasitoid species attacking a single species than attacking multiple hosts within each ant genus where the immunological system might be more similarthen the asymmetry hypothesis could also help explain phorid speciation. The Conspicuousness-Abundance-Stability Hypothesis There might be a reason why every species of Atta has phorids attacking them while the same does not occur in Acromyrmex. One obvious hypothesis could be the conspicuousness and temporal-spatial stability of Atta which assures an enormous amount of resources available, relative to that for Acromyrmex [ 11 ].
In fact, the species richness and abundance of hosts were the main determinants of phorid richness at the nest, hectare, and local scale, although, for the latter scale, climatic variables emerged in importance [ 12 ]. Moreover, the conspicuousness of the host was also important in explaining parasitoid richness [ 55 ].
In conjunction with the intriguing pattern that leaf-cutter phorids do not attack both genera of potential hosts, this latter result suggests that past competition could have led to segregation across different host niche axes [ 2025 ] whereas ecological conditions at local scales, with the availability of particular combination of hosts, may produce the final assembly that minimizes host overlap.
Biological Control of Leaf-Cutter Ants by Parasitoids Leaf-cutter ant parasitoids exhibit several features that suggest they may become promising biological controls of leaf-cutter ants. In addition, they have a strong negative impact on ant foraging in the field. However, it should be highlighted that the single use of parasitoids may not be able to control leaf-cutter ants. The hundred to million individuals involved in the nests of this successful group of ants will certainly need the use of a combination of different strategies to control them.
Promising Lines of Research Over half of the 67 known species 38 have been described since Feener Jr. In addition, a great amount of information has been gathered on the basic biology of these newly discovered species, as well as that of longer known taxa. This information is also fundamental to any applied utilization of these parasitoids for biological control, including the descriptions of life cycles of many of the extant species, their host associations, the discovery of two guilds defined by the host genus, and the oviposition behaviors and response by their hosts under different circumstances.
However, much waits to be studied and discovered about the fascinating interactions within this system. To help guide us through the many possible lines of research proposed within the body of this text, I list here the lines of research that I consider to be most important. Acknowledgments The author thanks all colleagues that have been contributing through time to this fascinating system of study, especially to Dr. Elizalde and her current one Lic. Patrock kindly reviewed this paper, improving it, as he always does.
Drawings were made by A. Phoridae ant parasitoids and their potential to control imported Solenopsis fire ants Hymenoptera: View at Google Scholar D. Phoridaea parasitoid of the giant tropical ant Paraponera clavata Hymenoptera: Castro Della Lucia, Ed. View at Google Scholar R. Phoridae that parasitize leaf-cutter and army ants Hymenoptera: Ribeiro do Carmo, and I. View at Google Scholar L.
View at Google Scholar B. View at Google Scholar M. Phoridae associated with leaf-cutter ants and army ants Hymenoptera: Phoridaeparasitoids of Atta vollenweideri Hymenoptera: Phoridae that parasitize leaf-cutter ants Hymenoptera: Phoridae that parasitize ants Hymenoptera: Phoridaeparasites of leaf-cutter ants Hymenoptera: Phoridae and its host, the leaf-cutting ant Atta sexdens rubropilosa Hymenoptera: Phoridaeand defense behavior by its leaf-cutting ant host Atta cephalotes Hymenoptera: Received Oct 26; Accepted Jun 7.
This article has been cited by other articles in PMC. Abstract Host-searching and oviposition behaviors of parasitoids, and defensive responses of the hosts, are fundamental in shaping the ecology of host-parasitoid interactions.
In order to uncover key behavioral features for the little known interactions between phorid parasitoids Diptera: Phoridae and their leaf-cutting ant hosts Formicidae: Attinihost-related behavioral strategies i. Data was collected at 14 localities, one of them characterized by its high species richness for this host-parasitoid system. Phorid species showed both great variation and specificity in attacking behaviors. Some chose their hosts using either an ambush or an actively searching strategy, while some species attacked ants on different body parts, and specialized on ants performing different tasks, such as when ants were foraging, removing wastes to refuse piles, or repairing the nest.
Combining all the behaviors recorded, most phorid species differed in performance in at least one, making it possible to recognize species in the field through their behavior. Phorid species that attacked hosts with greater activity levels showed overall higher attack rates, although there was no significant correlation between attack rates by most phorid species and ant activity outside the nest while parasitoids were attacking.
The presence of phorids was a significant determinant for the presence of defensive behaviors by the ants. Although ant species varied in the incidence levels of these defensive behaviors, most ant species reacted against different phorids by utilizing similar behaviors, in contrast to what parasitoids do.
General features of the observed phorid-ant interactions were parasitoid specialization and corresponding high interspecific variation in their behaviors, while their hosts showed generalized responses to attacks with high intraspecific variation.
- Behavioral Strategies of Phorid Parasitoids and Responses of Their Hosts, the Leaf-Cutting Ants
Behavioral patterns as well as specific features of these ant-parasitoid interactions are described, and their ecological importance discussed. Introduction Any successful endoparasitoid must overcome a hierarchical set of barriers in order to oviposit in a host. The parasitoid must locate and encounter its prey, and, upon doing so, manage to insert an egg while overcoming the host's physical and behavioral defenses Vinson ; Godfray Several aspects of the behavior of parasitoids can affect the response of the hosts, making the defensive response of the hosts more or less effective in preventing the parasitoid from leaving offspring.
In general, behavioral mechanisms of hosts against parasites are the first line of defense Kenneth For dipteran parasitoids with mobile adult hosts, behavioral defenses are a critical element to overcome, and one that effectively determines the host range of these flies Feener and Brown Acromyrmex and Atta cut plant tissue from surrounding vegetation and carry the pieces back to their nest using a persistent trail network Kost et al.
When ant workers are outside the nest for any reason, they could be attacked by phorid Diptera: Phoridae endoparasitoids, which use a piercing ovipositor to insert an egg inside the worker's body. The phorid species that use Atta as hosts do not use Acromyrmex ants Elizalde and Folgarait The host-related behaviors i.
Moreover, no generalizations have been made for any of these parasitoids in terms of host-related behaviors. Reduction in the foraging activity of the leaf-cutting ant Atta sexdens caused by the phorid Neodohrniphora sp. Entomologia Experimentalis et Applicata, Formicidae em Porto Nacional, TO. Parasitism characteristics of two phorid fly species in relation to their host, the leaf-cutting ant Atta laevigata Smith Hymenoptera: Parasitismo por Neodohrniphora spp. Revista Brasileira de Entomologia, Superparasitism and host discrimination by Neodohrniphora elongata Diptera: Phoridaea parasitoid of the leaf-cutting ant Atta sexdens rubropilosa Hymenoptera: Taxonomic revision of Neodohrniphora, subgenus Eibesfeldtphora Diptera: Differential host use by Neotropical phorid flies Diptera: Phoridae that are parasitoids of ants Hymenoptera: Behavior and host location cues of Apocephalus paraponerae Diptera: Phoridaea parasitoid of the giant tropical ant, Paraponera clavata Hymenoptera: New species and new records of Apocephalus Coquillett Diptera: Phoridae that parasitize ants Hymenoptera: