Formicidae Research Articles

Species Discrimination of Three Odontomachus (Formicidae: Ponerinae) Species in Thailand Using Outline Morphometrics.

Simple SummaryDetermination of species in the ant genus Odontomachus, which is a venomous group of ants, may require the use of highly trained entomologists. In Thailand, three species are very similar and difficult to distinguish: O. monticola, O. rixosus, and O. simillimus. In such a situation, a complementary technique not requiring highly specialized entomological knowledge is welcome. The geometric morphometric approach has proven to be this sort of tool, especially powerful for morphologically close or even cryptic species. In its most recent development, the geometric method uses the relative position of some anatomical landmarks. However, in worker ants these landmarks are few in number and can be difficult to assess without dissection. Here, therefore, we use the outline-based approach, an alternative geometric technique that has not yet been tested in ants. We show that the simple outline of the head contains a strong taxonomic signal, much stronger than the one obtained from the pronotum shape. The outline technique therefore represents a promising approach to aid in the determination of ant species.All members of the ant genus Odontomachus Latreille, 1804 are venomous ants. Four species in this genus have been identified from Thailand: Odontomachus latidens Mayr, 1867; O. monticola Emery, 1892; O. rixosus Smith, 1757; and O. simillimus Smith, 1758. The three latter species are available and have been used for an outline morphometric study. They display similar morphology, which makes their distinction very difficult except for highly qualified individuals. A total of 80 worker specimens were studied, exploring the contour shapes of their head and pronotum as possible taxonomic characters. The size of each body part was estimated determining the contour perimeter, the values for which were largely overlapping between O. rixosus and O. simillimus; most O. monticola specimens exhibited a significantly larger size. In contrast to the size, each contour shape of the head or pronotum established O. rixosus as the most distinct species. An exploratory data analysis disclosed the higher taxonomic signal of the head contour relative to the pronotum one. The scores obtained for validated reclassification were much better for the head (99%) than for the pronotum (82%). This study supports outline morphometrics of the head as a promising approach to contribute to the morphological identification of ant species, at least for monomorphic workers.

The response of ants to climate change.

Ants (Hymenoptera: Formicidae) are one of the most dominant terrestrial organisms worldwide. They are hugely abundant, both in terms of sheer numbers and biomass, on every continent except Antarctica and are deeply embedded within a diversity of ecological networks and processes. Ants are also eusocial and colonial organisms—their lifecycle is built on the labor of sterile worker ants who support a small number of reproductive individuals. Given the climatic changes that our planet faces, we need to understand how various important taxonomic groups will respond; this includes the ants. In this review, we synthesize the available literature to tackle this question. The answer is complicated. The ant literature has focused on temperature, and we broadly understand the ways in which thermal changes may affect ant colonies, populations, and communities. In general, we expect that species living in the Tropics, and in thermally variable microhabitats, such as the canopy and leaf litter environments, will be negatively impacted by rising temperatures. Species living in the temperate zones and those able to thermally buffer their nests in the soil or behaviorally avoid higher temperatures, however, are likely to be unaffected or may even benefit from a changed climate. How ants will respond to changes to other abiotic drivers associated with climate change is largely unknown, as is the detail on how altered ant populations and communities will ramify through their wider ecological networks. We discuss how eusociality may allow ants to adapt to, or tolerate, climate change in ways that solitary organisms cannot and we identify key geographic and phylogenetic hotspots of climate vulnerability and resistance. We finish by emphasizing the key research questions that we need to address moving forward so that we may fully appreciate how this critical insect group will respond to the ongoing climate crisis.

Brood as booty: the effect of colony size and resource value in social insect contests

AbstractAnimals engage in contests for access to resources like food, mates, and space. Intergroup contests between groups of organisms have received little attention, and it remains unresolved what information groups might use collectively to make contest decisions. We staged whole-colony contests using ant colonies (Temnothorax rugatulus), which perceive conspecific colonies as both a threat and resource from which to steal brood. We recorded individual behaviors and used demographic characteristics as proxies for resource value (number of brood items) and fighting ability (number of workers). We found that ants altered their fighting effort depending on the relative number of workers of their opponent. Although the proximate mechanism for this ability remains uncertain, we found that colonies increased fighting when their opponent had relatively more brood, but not if opposing colonies had relatively many more workers. This suggests that ant colonies can use information about opposing colonies that shapes contest strategies. Further, the behavior of opposing colonies was strongly correlated with each other despite colony size differences ranging from 4% to 51%, consistent with the hypothesis that colonies can use opponent information. The behavior of a distributed, collective system of many individuals, like a eusocial insect colony, thus fits several predictions of contest models designed for individuals if we consider the gain and loss of worker ants analogous to energetic costs accrued during typical dyadic contests.

The Skeletomuscular System of the Mesosoma ofFormica rufaWorkers (Hymenoptera: Formicidae)

AbstractThe mesosoma is the power core of the ant, containing critical structural and muscular elements for the movement of the head, legs, and metasoma. It has been hypothesized that adaptation to ground locomotion and the loss of flight led to the substantial rearrangements in the mesosoma in worker ants and that it is likely the ant mesosoma has undergone functional modifications as ants diversified into different ecological and behavioral niches. Despite this importance, studies on the anatomy of the ant mesosoma are still scarce, and there is limited understanding of important variation of internal structures across the ant phylogeny. Recent advances in imaging techniques have made it possible to digitally dissect small insects, to document the anatomy efficiently and in detail, and to visualize these data in 3D. Here we document the mesosomal skeletomuscular system of workers of the red wood ant, Formica rufa Linnaeus, 1761, and use it to establish a 3D atlas of mesosomal anatomy that will serve as reference work for further studies. We discuss and illustrate the configuration of the skeletomuscular components and the function of the muscles in interaction with the skeletal elements. This anatomical evaluation of a ‘generalized’ ant provides a template for future studies of the mesosoma across the radiation of Formicidae, with the ultimate objective of synthesizing structural, functional, and transformational information to understand the evolution of a crucial body region of ants.

Computational exploration of treadmilling and protrusion growth observed in fire ant rafts.

Collective living systems regularly achieve cooperative emergent functions that individual organisms could not accomplish alone. The rafts of fire ants (Solenopsis invicta) are often studied in this context for their ability to create aggregated structures comprised entirely of their own bodies, including tether-like protrusions that facilitate exploration of and escape from flooded environments. While similar protrusions are observed in cytoskeletons and cellular aggregates, they are generally dependent on morphogens or external gradients leaving the isolated role of local interactions poorly understood. Here we demonstrate through an ant-inspired, agent-based numerical model how protrusions in ant rafts may emerge spontaneously due to local interactions. The model is comprised of a condensed structural network of agents that represents the monolayer of interconnected worker ants, which floats on the water and gives ant rafts their form. Experimentally, this layer perpetually contracts, which we capture through the pairwise contraction of all neighboring structural agents at a strain rate of . On top of the structural layer, we model a dispersed, on-lattice layer of motile agents that represents free ants, which walk on top of the floating network. Experimentally, these self-propelled free ants walk with some mean persistence length and speed that we capture through an ant-inspired phenomenological model. Local interactions occur between neighboring free ants within some radius of detection, R, and the persistence length of freely active agents is tuned through a noise parameter, η as introduced by the Vicsek model. Both R and η where fixed to match the experimental trajectories of free ants. Treadmilling of the raft occurs as agents transition between the structural and free layers in accordance with experimental observations. Ultimately, we demonstrate how phases of exploratory protrusion growth may be induced by increased ant activity as characterized by a dimensionless parameter, . These results provide an example in which functional morphogenesis of a living system may emerge purely from local interactions at the constituent length scale, thereby providing a source of inspiration for the development of decentralized, autonomous active matter and swarm robotics.

Metabolic scaling of fire ants (Solenopsis invicta) engaged in collective behaviors.

ABSTRACTDuring flash floods, fire ants (Solenopsis invicta Buren) link their bodies together to build rafts to stay afloat, and towers to anchor onto floating vegetation. Can such challenging conditions facilitate synchronization and coordination, resulting in energy savings per capita? To understand how stress affects metabolic rate, we used constant-volume respirometry to measure the metabolism of fire ant workers. Group metabolic rates were measured in a series of conditions: at normal state, at three elevated temperatures, during rafting, and during tower-building. We hypothesized that the metabolic rate of ants at various temperatures would scale isometrically (proportionally with the group mass). Indeed, we found metabolic rates scaled isometrically under all temperature conditions, giving evidence that groups of ants differ from entire colonies, which scale allometrically. We then hypothesized that the metabolism of ants engaged in rafting and tower-building would scale allometrically. We found partial evidence for this hypothesis: ants rafting for short times had allometric metabolic rates, but this effect vanished after 30 min. Rafting for long times and tower-building both scaled isometrically. Tower-building consumed the same energy per capita as ants in their normal state. Rafting ants consumed almost 43% more energy than ants in their normal state, with smaller rafts consuming more energy per capita. Together, our results suggest that stressful conditions requiring coordination can influence metabolic demand. This article has an associated First Person interview with the first author of the paper.

Distinguishing Symbiotic Partners of Acropyga Ants from Free-Living Soil Inhabitants.

The fruitful study of associations between ants and scale insects yields insight into the mechanisms that shape these symbioses. Field collections provide the basic information linking partnered species, and as such it is critical that collection techniques from the field reflect true species-to-species partnerships in the published literature. It is equally critical that such practices limit the potential for mistaking free-living "neighbors" for symbiotic partners and publishing erroneous associations. This article describes a protocol for collecting subterranean scale insects and associated Acropyga Roger ants, which relies upon the activity of worker ants to sort and distinguish symbionts from free-living scale insects that happen to live near the colony. By collecting samples of ants and scales into nest boxes and allowing a resting period of several hours, worker ants will gather symbiotic partners into dense, protected clusters in which symbionts are actively tended. Free-living scale insects neighboring the colony can be collected from soil along with colony samples, but these free-living individuals are excluded from protective clusters and ignored by workers. Following confirmation of ant attendance, true symbiotic partners can be confidently collected, preserved, and recorded for future study. We illustrate the value of employing this collection protocol using a case study from Peru.

Cloning and Functional Characterization of a Double-Stranded RNA-Degrading Nuclease in the Tawny Crazy Ant (Nylanderia fulva).

RNA interference is a powerful tool that post-transcriptionally silences target genes. However, silencing efficacy varies greatly among different insect species. Recently, we attempted to knock down some housekeeping genes in the tawny crazy ant (Nylanderia fulva), a relatively new invasive species in the southern United States, but only achieved relatively low silencing efficiency when dsRNA was orally administered. Here, we detected divalent cation-dependent, dsRNA-degrading activity in the midgut fluid of worker ants in ex vivo assays. To determine whether dsRNA degradation could contribute to low effectiveness of oral RNAi in N. fulva, we cloned its sole dsRNase gene (NfdsRNase). The deduced amino acid sequence contained a signal peptide and an endonuclease domain. Sequence alignment indicated a high degree of similarity with well-characterized dsRNases, particularly the six key residues at active sites. We also identified dsRNase homologs from five other ant species and found a tight phylogenetic relationship among ant dsRNases. NfdsRNase is expressed predominantly in the abdomen of worker ants. Oral delivery of dsRNA of NfdsRNase significantly reduced the expression of NfdsRNase transcripts, and substantially suppressed dsRNA-degrading activity of worker ants’ midgut fluids as well. Our data suggest that dsRNA stability in the alimentary tract is an important factor for gene silencing efficiency in N. fulva, and that blocking NfdsRNase in gut lumen could potentially improve RNAi, a novel pest management tactic in control of N. fulva and other ant species.

Evidence for the effect of brief exposure to food, but not learning interference, on maze solving in desert ants.

Theories of forgetting highlight 2 active mechanisms through which animals forget prior knowledge by reciprocal disruption of memories. According to "proactive interference," information learned previously interferes with the acquisition of new information, whereas "retroactive interference" suggests that newly gathered information interferes with already existing information. Our goal was to examine the possible effect of both mechanisms in the desert ant Cataglyphis niger, which does not use pheromone recruitment, when learning spatial information while searching for food in a maze. Our experiment indicated that neither proactive nor retroactive interference took place in this system although this awaits confirmation with individual-level learning assays. Rather, the ants' persistence or readiness to search for food grew with successive runs in the maze. Elevated persistence led to more ant workers arriving at the food when retested a day later, even if the maze was shifted between runs. We support this finding in a second experiment, where ant workers reached the food reward at the maze end in higher numbers after encountering food in the maze entry compared to a treatment, in which food was present only at the maze end. This result suggests that spatial learning and search persistence are 2 parallel behavioral mechanisms, both assisting foraging ants. We suggest that their relative contribution should depend on habitat complexity.

Toxicity and Repellency of Magnolia grandiflora Seed Essential Oil and Selected Pure Compounds Against the Workers of Hybrid Imported Fire Ants (Hymenoptera: Formicidae).

We tested Magnolia grandiflora L. (Magnoliales: Magnoliaceae) seed essential oil and its pure compounds for their repellency and toxicity against workers of hybrid imported fire ants. Series of dosages were tested starting from 156 µg/g to the dose where the treatment failed. Workers removed significantly less sand from the vials with M. grandiflora seed essential oil and 1-octanol treated sand at serial dosages of 156-4.9 µg/g than the solvent control whereas the amount removed at 2.4-0.6 µg/g was similar to the solvent control. In 1-decanol treatments, workers removed significantly less sand at serial dosages of 156-0.15 µg/g than the solvent control whereas the removal of sand at the dose of 0.08 µg/g was similar to the solvent control. In DEET (N, N-diethyl-meta-toluamide) treatments, workers removed significantly less sand at serial dosages of 156-78 µg/g than the solvent control whereas the quantity of removed sand at 39 µg/g was similar to the solvent control. Based on the mean amount of sand removed, M. grandiflora essential oil, 1-decanol, and 1-octanol showed significantly higher repellency than DEET. 1-Decanol and 1-octanol, present in seed essential oil showed toxicity against fire ant workers. 1-Decanol with LC50 of 140.6 µg/g was the most toxic natural compound followed by 1-octanol (LC50 = 486.8 µg/g). Bifenthrin with LC50 value of 0.018 µg/g showed much higher toxicity than these natural compounds. High repellency and toxicity of 1-decanol makes it a natural compound of interest for further studies under field conditions.

To exchange or not to exchange liquid food: is that the question for foraging leaf‐cutting ant workers?

AbstractLeaf‐cutting ants forage fresh plants in the field to cultivate the symbiotic fungus in their nests. The trophallaxis rates in leaf‐cutting ants may be related to liquid foraging behavior and exchanging liquid food with other ants inside the nest. The liquid foraging and liquid food exchange in laboratory colonies of the leaf‐cutting ant Atta sexdens (L.) (Hymenoptera: Formicidae, Attini) were studied to test whether liquid food is transferred to inside‐nest workers by foragers. The foragers commonly ingested liquid when provided with a liquid source and performed different behaviors, such as self‐ and allogrooming, but without food exchange (oral trophallaxis) to the workers inside the nest. The liquid foraging was not related to food exchange with workers inside the nest. We suggest that liquid foraging meets the individual worker needs without liquid exchange among ants inside their colonies.

Searching Behavior in the Tropical Fire Ant Solenopsis geminata (Hymenoptera: Formicidae).

Social insects have evolved different search strategies to find target objects in unknown environments. In the present study, the searching behavior of the tropical fire ant Solenopsis geminata was investigated in a circular arena. The average time, search path, speed, and search patterns of worker ants in a circular arena were determined. The results showed that fire ant workers followed six major search patterns. The variation in the searching patterns of workers may explain the different levels of exploration. Most workers (56.8%) tended to search in small loops and progressively increase the search area size. These workers mostly turned in one direction, either clockwise or counterclockwise. More workers turned in a consistent pattern than in an inconsistent pattern. Moving speed was also higher in workers that maintained their turning directions than in those that changed directions. We thus propose that following search patterns consisting of loops of increasing size may be an effective strategy. The tropical fire ant S. geminata is a globally invasive species that was introduced to Taiwan 40 years ago and has continued to threaten residents. Based on behavioral studies of S. geminata, we may gain a better understanding of their exploratory behavior in the ecosystem in Taiwan.

Analysys of species diversity of ants (Hymenoptera: Formicidae) in Lviv (Ukraine)

Background. The paper presents the results of original research on the diversity of ants (Hymenoptera: Formicidae) in Lviv (Ukraine). In Ukraine, 146 species of ants from 39 genera of five subfamilies are known at present. Ants play an important role in ecosystems. They build their nests in the soil, which contributes to better soil formation. Ants are important links in trophic chains. They are the most adaptable to settling new territories. The diversity of ants in Lviv is potentially very high due to a good geographical location between Polissia and the Carpathians. However, today there are almost no articles on ants’ taxonomic groups in Lviv. This study aims to present new records of Lviv myrmecofauna, and to investigate ants’ seasonal rhythms. Materials and Methods. The objects of our research were ants (Formicidae), collected from three different park areas in Lviv, and the territories of the Botanical garden of Ivan Franko National University of Lviv between 2020 and 2021. Main sampling methods were hand collecting and usage of sweet baits (Romero, 1989). In addition, we investigated ants’ behavioral traits related to the winter dormancy state. Results and Discussion. We analyzed 90 samples of worker ants. In the course of identification, 20 different species belonging to seven genera (Formica Linnaeus, 1758, Lasius Fabricius, 1804, Camponotus Mayr, 1861, Myrmecina Curtis, 1829, Myrmica Latreille, 1804, Temnothorax Nylander, 1856 and Tetramorium Mayr, 1855) were found, which in turn belong to two subfamilies: Formicinae Lepeletier, 1836 and Myrmecinae Emery, 1877. Numerous species belong to genera Lasius, Formica, Myrmica, and Tetramorium, which are mentioned as common in Eastern Europe. Behavioral research related to hibernation shows that Formica polyctena Forster, 1850 begins to enter hibernation earlier than other species, namely on 30.09.21 at an average air temperature of +12 °C. They were the latest to leave this state, at the end of April 25.04.22 at the same temperature. On the other hand, Lasius niger (Linnaeus, 1758) remained active the longest in autumn, namely until 21.10.21 at a temperature of +3 °C, and came to the surface one of the earliest on 24.03.22 at +9 °C. Conclusion. We recorded 20 ant species that have not been mentioned for Lviv because of the absence of any published information. The data obtained within this study show the important role of botanical gardens in preserving the biodiversity of ants despite their small area. Therefore, the topic of the diversity of the myrmecofauna of Ukraine, and urban areas in particular, is relevant and insufficiently researched today.

Population and Nesting Behaviour of Weaver Ants, Oecophylla smaragdina from Meghalaya, India

Weaver ants are known for their unique nest-building skills using leaves and larval-silk as a binding agent. The weaver ants, Oecophylla smaragdina are present in large numbers in the Ri-Bhoi district, Meghalaya. Ri-Bhoi district is a hot and humid place with 22 -30°C. This is the first study from this region to examine the nesting behavior along with the population of these ants from here. It was noted that they build nests in different types of trees but it is more abundant in needlewood trees (Schima wallichi) locally known as ‘diengngan.’ From the central trunk of the S. wallichi tree, the nearest distance of the nest is about 0.7 m and the farthest up to 3.4 m. The nests of O. smaragdina are somewhat round-oval and use leaves of different sizes ranging from 8-32 cm2. The nests are made at a height ranging from 4-25 m and their average nest size is about 9,483 cm3. They utilize about twenty leaves with a specific number of chambers to keep their broods, the queen, and food. The number of worker ants, pupae, and larvae are variable in different nests because of nest size, location/height of the nests, and the trees. When the nest population increases, they locate a new spot and build a satellite nest where they get the right amount of sunlight and shelter from predators and adverse environmental factors. These weaver ants are also used as medicine, food and fish bait by the indigenous people in Meghalaya.

Dispersal of Phraortes illepidus (Phasmida: Phasmatidae) Eggs by Workers of the Queenless Ant, Pristomyrmex punctatus (Hymenoptera: Formicidae)

Eggs of some stick insects bear external appendages called capitula. Foraging worker ants attracted by capitula disperse eggs in a response similar to the responses of workers to elaiosome-bearing seeds of many plants. For this study, we conducted rearing experiments in the laboratory to elucidate the interspecific relation between the queenless ant, Pristomyrmex punctatus Smith, and the stick insect, Phraortes illepidus (Brunner von Wattenwyl) of which eggs bear capitula. Eggs of P. illepidus were proposed to P. punctatus in the laboratory. Capitula were removed from most of the eggs not only when ants were starved but also when ants were well-fed. In large rearing containers, eggs were transported by ants from their place of origin. Many eggs were transferred horizontally on the surface. Although some eggs were found in the artificial ant nests, it is likely that stick insects are not in active ant nests at the time of hatching in nature because of P. punctatus nest-moving habits. The percentage of eggs buried in the sand was small. Furthermore, most of the buried eggs were found at less than 3 cm depth. Results show that many P. illepidus hatchlings can reach host plants safely without being attacked by ant workers. These results suggest that P. punctatus can be a good partner of P. illepidus. Ants disperse eggs of slow-moving stink insects in exchange for some nutrition from capitula.

Postmortem Evaluation of Rabbit Carcasses Using Insect Populations in Keffi Nasarawa State, Nigeria

Untimely, forceful, and unexpected death is inevitable and common worldwide. Evidence for causes of death may be obtained through the knowledge of insects’ successional pattern and postmortem interval on dead carcasses. Two rabbits (Lepus cuniculus) weighing 2.5 kg each were used as the experimental animals. The rabbits were sacrificed by poisoning and stabbing, postmortem evaluation was achieved by taking record of the insect’s successional pattern. The insects’ successional pattern revealed the following insects’ species in order in which they arrived on the carcasses: Musca domestica, Lucilia sericata, Chrysomya albiceps, Dermestes maculatus, and Armadillidium vulgare (usual sp). The family Formicidae were represented by two unidentified species. M. domestica arrived first on the stabbed carcass while L. sericata on poisoned carcass. A total of 105±50 insects were collected throughout the study period, with stabbed rabbit contributing 61±10 and poisoned 44±60 insects’ species. Variation in the number of forensically important insects’ species encountered in the study site did not show any significant difference (p>0.05) in relation to each decomposition stage. There was however a significant difference (p<0.05) between insects’ relative abundance and mode of killing. Insect evidence was found 3 minutes after death on the stabbed carcass and 3 days after on the poisoned carcass. The study has shown that insects' population can be used to establish postmortem evidence in rabbit carcasses.

Similarities in Recognition Cues Lead to the Infiltration of Non-Nestmates in an Ant Species.

Chemical cues are among the most important information-sharing mechanisms in insect societies, in which cuticular hydrocarbons play a central role, e.g., from nestmate recognition to queen signaling. The nestmate recognition mechanism usually prevents intruders from taking advantage of the resources stored in the nest. However, nestmate recognition is not unconditionally effective, and foreign individuals can sometimes infiltrate unrelated nests and take advantage of the colony resources. In this study, we investigated the role of overall colony odor profiles on the ability of conspecific workers to drift into unrelated colonies. We hypothesized that drifters would have higher chances of success by infiltrating colonies with the odor profiles most similar to their own nest, avoiding being detected as non-nestmates. By performing a drifting bioassay, we found that workers of the ant Formica fusca infiltrated unrelated conspecific colonies at a rate of 2.4%, significantly infiltrating colonies displaying CHC profiles most similar to their natal nests. Notably, methyl branched hydrocarbons seem to play a role as recognition cues in this species. In addition, we show that environmental rather than genetic factors are responsible for most contributions on the CHC phenotype, presenting ca. of 50% and 27.5% of explained variation respectively, and playing a major role in how worker ants detect and prevent the infiltration of non-nestmates in the colony. Hence, relying on cuticular hydrocarbons similarities could be a profitably evolutionary strategy by which workers can identify conspecific colonies, evade detection by guards, and avoid competition with genetic relatives.

Worker ants vault to queenly rank after just one gene turns on

Worker ants vault to queenly rank after just one gene turns on

Identification of the Trail Pheromone of the Pavement Ant Tetramorium immigrans (Hymenoptera: Formicidae).

Four species of Tetramorium pavement ants are known to guide foraging activities of nestmates via trail pheromones secreted from the poison gland of worker ants, but the trail pheromone of T. immigrans is unknown. Our objectives were to (1) determine whether poison gland extract of T. immigrans workers induces trail-following behavior of nestmates, (2) identify the trail pheromone, and (3) test whether synthetic trail pheromone induces trail-following behavior of workers. In laboratory no-choice bioassays, ants followed poison-gland-extract trails farther than they followed whole-body-extract trails or solvent-control trails. Gas chromatographic-electroantennographic detection (GC-EAD) analyses of poison gland extract revealed a single candidate pheromone component (CPC) that elicited responses from worker ant antennae. The CPC mass spectrum indicated, and an authentic standard confirmed, that the CPC was methyl 2-methoxy-6-methylbenzoate (MMMB). In further laboratory no-choice bioassays, ants followed poison-gland-extract trails (tested at 1 ant equivalent) and synthetic MMMB trails (tested at 0.35 ant equivalents) equally far, indicating that MMMB is the single-component trail pheromone of T. immigrans. Moreover, in laboratory two-choice bioassays, ants followed MMMB trails ~ 21-times farther than solvent-control trails. In field settings, when T. immigrans colonies were offered a choice between two paper strips treated with a synthetic MMMB trail or a solvent-control trail, each leading to an apple bait, the MMMB trails efficiently recruited nestmates to baits.

Ant (Hymenoptera: Formicidae) ‐ aphid (Hemiptera: Aphididae) interactions in different habitats from Turkey with new mutualistic associations

AbstractThis study aimed to investigate the interactions between ants and aphids on host plants in different habitats located in the northwestern part of Turkey. A total of 26 ant species belonging to 13 genera and 3 subfamilies from the family Formicidae (Hymenoptera) were found associated with 52 aphid species belonging to 22 genera from the family Aphididae (Hemiptera: Aphidoidea) on 66 host plant species from 24 plant families.In total, 132 tritrophic ants–aphids–host plants interactions including new associations were revealed.Also, we present results on the interactions of ants–aphids–host plants in different habitats such as cultivated, uncultivated and urban areas. About 85 tritrophic interactions of ants–aphids–host plants were revealed in cultivated, 27 tritrophic interactions in uncultivated and 20 tritrophic interactions in urban areas. Tritrophic interactions were more diverse in cultivated areas than uncultivated and urban areas.Our results reveal that the interactions between ants and aphids are highly diverse and that they vary on host plants in different habitats. It may be thought that this is due to the specialization resulting from the high diversity of host plants of aphids in cultivated areas and increased the presence of ants.