Plagiolepis Pygmaea Research Articles

Ant Community Is Not Influenced by the Addition of Olive Mill Pomace Compost in Two Different Olive Crop Managements.

Industrial production of olive oil generates large amounts of solid waste called 'alperujo'. Its compost can fertilize many crops, especially olives. Furthermore, superintensive orchards are increasing their surface globally due to higher production and savings in different costs. Ants are considered an important part of the arthropod community in olive orchards and could even play a significant role in pest control. The tree canopy and ground were sampled to compare the ant assemblage in plots fertilized with compost and mineral products in two groves with different types of crop management (superintensive and traditional) over two years. The numbers of ants in both types of fertilization in each grove were not statistically different (p > 0.05), indicating that the type of fertilization did not have a significant impact on its populations in the ground or in the canopy, but the number of individuals was significantly higher in the superintensive grove than in the traditional grove (both in the ground and in the canopy, p < 0.01). The most frequent species in the ground were Pheidole pallidula, Plagiolepis smitzii and Aphaenogaster senilis (superintensive grove) and Pheidole pallidula, Tetramorium gr semilaeve, Plagiolepis pygmaea, and Tapinoma nigerrimum (traditional grove). In the canopy, the most frequent species were Plagiolepis spp. in both groves. Differences in ant densities and species between the groves could be due to the different management, especially of the soil, but it must be confirmed using more replicas and longer periods of study.

Diversity of ant species (Hymenoptera: Formicidae) from the Republic of Moldova

Ants are an important group of insects for the normal functioning of ecosystems, with a major influence on their habitats. The paper includes the data from literature, collections made between 2019-2022 and the specimens stored in the Museum of Entomology of the Institute of Zoology. As a result of the research carried out on the territory of the Republic of Moldova, a total of 65 species of ants were identified, of which the subfamily Ponerinae, genus Ponera and 7 species –Camponotus piceus, Cardiocondyla stambuloffii, Formica glauca, Lasius distinguendus, Plagiolepis pygmaea, Ponera coarctata and Temnothorax corticalis are new for the fauna of the country.

Ant attendance does not necessarily imply protection of aphids from their arthropod natural enemies

Abstract Many ants and hemipterans are bound by a mutualistic relationship (trophobiosis) which represents an ecological keystone: ants receive food (honeydew) providing different kinds of protection. Partner protection against arthropod natural enemies is considered to be frequent and to interfere with biological control strategies of hemipteran pests. We carried out an ant‐exclusion field experiment in a fava bean (Vicia faba) plantation in Italy to monitor the abundance and behaviour of the ants (Plagiolepis pygmaea, Tetramorium semilaeve and the exotic Nylanderia jaegerskioeldi) and their relationship with facultative mutualist (Aphis fabae) and non‐mutualist (Megoura viciae) aphids, the arthropod natural enemies of the aphids, and extrafloral nectaries. Ants concentrated their activity on the attendance of facultative mutualist aphids much more than on the extrafloral nectaries. The ant‐exclusion treatment had no effect on the abundance of M. viciae and on the parasitization rate of A. fabae, while it reduced the abundance of A. fabae, aphid predators, and aphid parasitoids. Our results demonstrate that ant attendance does not imply the protection of aphids from arthropod natural enemies and suggest that the identity of the ant species involved is important for the outcome. As relatively few species have been studied in this regard, extending our knowledge to the role of more ant species is desirable to understand the ecology and evolution of ant‐aphid mutualisms and to refine integrated control strategies of aphid pests.

Natural Repellents as a Method of Preventing Ant Damage to Microirrigation Systems.

Simple SummaryAnts play an essential role in most agroecosystems. However, these insects can occasionally be detrimental to agricultural microirrigation equipment by chewing on tubing parts and causing uneven water distribution along the crops. One of the alternatives traditionally proposed to avoid this damage is the incorporation of substances into the tube material that deter or reduce chewing activity. However, the few attempts made prior to this research were unsuccessful due to the unsuitability of the selected substances and the methods used to integrate them into the tubing. In this study, we assessed the protective efficacy of this method in pipes used for subsurface drip irrigation (SDI). Unlike traditional attempts, we selected nontoxic compounds previously proven to be repellent against ants and integrated them into drip tubing through complex processes such as plastic compounding, injection and extrusion. The use of this type of tubing in a crop where significant ant damage is often reported revealed minimum damage when compared to control tubing containing no repellent additives. This suggests the efficiency of this method in providing protection against ants, but further studies are recommended prior to the commercialization of the designed system.Ants are important because they damage agricultural equipment, including microirrigation systems. The aim of this research was to assess the efficiency of the incorporation of repellents in drip irrigation tubing as a method of protection against ant damage. Unlike previous studies, we tested a series of nontoxic compounds that are repellent to ants. First, we assessed their repellent effects on a local ant species via olfactometer trials. Then, the candidates showing the best results (cinnamon essential oil, p-anisaldehyde and ethyl anthranilate) were incorporated via compounding, injection and extrusion to polyethylene tubing to test their efficiency in the field. Field tests showed high damage levels in the control tubing containing no repellents, presumably caused by up to six different ant species (Cardiocondyla batesii, Plagiolepis pygmaea, P. schmitzii, Solenopsis sp., Tapinoma nigerrimum and Tetramorium semilaeve). In contrast, the pipes containing the three selected compounds remained almost intact, with the treatment including ethyl anthranilate showing no damage at all. These results suggest the strong repellent potential of the selected compounds, even when integrated into plastic, as well as the apparent success of the proposed methodology against the damage caused by ants. The diversity of damage-causing agents that exist in or above the soil strongly encourages further studies to determine the overall efficiency of repellents in protecting irrigation pipes.

A checklist of ants (Hymenoptera: Formicidae) in northern Shaanxi Province, China, with one new species of genus Proformica Ruzsky, 1902

• A new species Proformica muusensis sp. nov. , is described. • Seven species from Shaanxi Province are reported for the first time. • A preliminary checklist of ants of the northern Shaanxi is provided. A preliminary checklist of the ants of northern Shaanxi is presented based on an evaluation from June 2018 to September 2020. Seven species are reported from Shaanxi for the first time: Formica approximans Wheeler, 1933; Formica clara Forel, 1886; Messor aralocaspius (Ruzsky, 1902); Plagiolepis pygmaea (Latreille, 1798); Tapinoma rectinotum Wheeler, 1927; Tetramorium chefketi Forel, 1911; Tetramorium tsushimae Emery, 1925 and Temnothorax ruginosus Zhou, Huang, Yu & Liu, 2010. A new species of genus Proformica Ruzsky, 1902, Proformica muusensis sp. nov. , is described based on the morphology and molecular method. In total, three subfamilies with 34 valid ant species in 15 genera are reported in our checklist.

Contrasting responses of native ant communities to invasion by an ant invader, Linepithema humile

Invasive alien species pose a serious threat to the integrity and function of natural ecosystems. Understanding how these invaders alter natural communities is therefore an important aspect in predicting the likely future outcomes of biological invasions. Many studies have documented the consequences of invasive alien species on native community structure, through the displacement and local extinction of native species. However, sampling methods and intensities are rarely standardised across such studies, meaning that it is not clear whether differences in response among native communities to the same invader species are due to biological differences between the invaded regions, or differences in the methodologies used. Here we use a matched sampling methodology to compare the effects of the Argentine ant (Linepithema humile Mayr) on native ant community assemblages in two distinct biogeographical regions that share similar ecologies: Girona (Spain) and Jonkershoek Nature Reserve (South Africa). We found a strong negative association between L. humile presence and native ant species richness within both geographic regions. However, the effects differed between the two study regions: in Girona, a single native ant species (Plagiolepis pygmaea) persisted in invaded sites; by contrast, substantially more native ant species persisted at invaded sites in Jonkershoek Nature Reserve. In addition, in Jonkershoek Nature Reserve, the abundance of certain native species appeared to increase in the presence of L. humile. This study therefore demonstrates the potential variable effects of an invasive species in contrasting locations within different biogeographical regions. Future work should explore the causes of this differential resistance among communities and expand standardised sampling approaches to more invaded zones to further explore how local biotic or abiotic conditions of a region determine the nature and extent of impact of L. humile invasion on native ant communities.

Impact of the Invasive Argentine Ant in Citrus Agroecosystems: Effects on the Diversity and Frequency of Native Ant Species Foraging on Tree Canopy.

Simple SummaryWe aimed at assessing the impact of the Argentine ant invasion on the native ant community in citrus ecosystems. We compared the Argentine ant’s invaded and uninvaded citrus orchards in the south of Portugal, estimating species richness and the frequency of ant assemblages foraging on the tree canopy. The results suggest that the Argentine ant has a negative impact on the native ant community structure, markedly reducing the diversity and frequency of native species. This impact was more or less pronounced depending on the season. Possible implications for citrus pest management are discussed.The invasion of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera, Formicidae) can alter the entire ecosystem with serious impacts on the native community structure (e.g., ant diversity) and processes (e.g., trophic interactions) leading to biodiversity loss and pest outbreaks. Most studies addressing these impacts have been conducted in natural or semi-natural areas, few are those conducted in agricultural ecosystems, such as citrus orchards. These are dominant agricultural ecosystems in Mediterranean landscapes. Furthermore, most studies have been conducted in a short span, not evidencing seasonal fluctuations. In this work, we assessed the ecological impact of the Argentine ant on the native ant communities in citrus orchards, in the region of Algarve, southern Portugal. By using principal response curve, we compared seasonal variation on ant assemblages in invaded and uninvaded citrus orchards foraging on tree canopy from a two-year sampling. The Argentine ant had a marked negative impact on the native ant community foraging on citrus canopy. In the uninvaded orchards, the native ant community had a rich assemblage composed of 16 ant species, in its majority (72%) controlled by the dominant species Lasius grandis Forel, Tapinoma nigerrimum (Nylander) and/or Pheidole pallidula (Nylander). In the invaded orchards, the native ant community was poorer and highly modified, mostly dominated by the Argentine ant (80%). Apparently, the only native ant species not affected by the presence of the Argentine ant was Plagiolepis pygmaea (Latreille). A significant negative effect was found between the proportion of infested trees by L. humile and the number of native ant species per orchard. Differences in the native ant community in the invaded and uninvaded orchards persisted over seasons and years. However, negative impacts were higher in the spring and summer, and less pronounced in the autumn. We discuss implications for citrus pest management.

Diversity, spatial distribution, and sampling for ant management decision‐making in integrated pest management programs in citrus groves

AbstractAnts play important ecological roles, such as predation on other arthropods, seed dispersal, and soil structure maintenance. In citrus agroecosystems, ants are considered a secondary pest. The damage they cause is indirect through the disruption of the biological control of pests, especially honeydew producers. In integrated pest management programs, adequate and precise sampling methods are required to accurately determine the need for chemical ant control to minimize the economic and environmental costs of unnecessary chemical treatments and to reduce the risk of crop loss by pests. In Mediterranean citrus groves, eight ant species that differed in abundance and frequency have been found foraging on citrus trees: Lasius grandis Forel, Pheidole pallidula (Nylander), Plagiolepis pygmaea (Latreille), Formica gerardi Bondroit, Formica rufibarbis Fabricius, Camponotus sylvaticus (Olivier), Linepithema humile (Mayr), and Tapinoma erraticum (Latreille) (all Hymenoptera: Formicidae). The trunk was selected as the most efficient sampling unit to establish the monitoring method. Aggregation indices on the trunk of these species were calculated, and enumerative and binomial sampling methods were developed for the most frequent species, L. grandis and Ph. pallidula. Ant species differed in spatial distributions within citrus orchards, and required different sample sizes to estimate population abundance. The minimum sample size required, taking into account the maximum average abundance found – 44.1 L. humile, 17.3 L. grandis, and 3.5 Ph. pallidula per trunk per min –, would be 28, 25, and 54 trees, respectively.

Five new records of ants (Hymenoptera: Formicidae) from Morocco.

A recent catalogue of the rich ant fauna of Morocco included 214 species, with later studies adding an additional 12 species. Following recent fieldwork in the north of Morocco, we report five new records for the country (Plagiolepis pygmaea Latreille, 1798, Ponera testacea Emery, 1895, Strumigenys tenuipilis Emery, 1915, Temnothorax pardoi Tinaut, 1987, and Tetramorium parvioculum Guillem & Bensusan, 2009) and we present new data on the distribution and natural history of six additional species. This work brings the total number of ants known from Morocco to 233, taking into account two species which were omitted in the list of Cagniant.

No reversion to single mating in a socially parasitic ant

Social Hymenoptera are ideal biological models for the study of the selective forces affecting the evolution of multiple mating (polyandry), because sister species can evolve different lifestyles and mating strategies. Single mating is predicted in workerless social parasites, because the key benefit of multiple mating in social insects, that is, the increase in genetic diversity among worker offspring, does not hold for workerless species. We compared the queen mating frequency between the ant Plagiolepis pygmaea and its derived social parasite P.xene. Previous studies showed that queens of the host P.pygmaea are obligately polyandrous. Here, pedigree analyses of mother-offspring combinations indicate that queens of the parasite P.xene did not revert to single mating; more than 50% of queens mated multiply, with 2-4 males. This result shows that reversal from multiple to single mating may be not selected in polyandrous social insect workerless parasites. We propose that such reversion does not occur when multiple mating is virtually cost free.

Attraction of ants by an invasive Acacia

Abstract. 1. Invasive plants are often released from the herbivores of their native range, but may also be deprived of their co-evolved mutualists. In southern Portugal Acacia dealbata has become naturalised in secondary woodland habitats and is apparently not damaged by local herbivores. It possesses inactive extra-floral nectaries (EFNs). 2. Artificial damage to leaves, mimicking herbivore attack, induced extra-floral nectar production on both adult trees and seedlings. This response was restricted to individual leaves rather than systemic. 3. Following EFN activation, trees were tended by the invasive Argentine ant Linepithema humile. Seedlings received a tenfold greater visitation rate from either L. humile or the native ant Plagiolepis pygmaea, which appears to displace the former. Eight days after the damage treatment the ants and nectar had largely gone. 4. There was no indication that either species of ant would defend the plant against potential herbivores. 5. This is the first recorded ant-plant interaction among two invasive species. Given the lack of natural herbivore damage and the absence of suitable ants in this novel community, nectar induction by A. dealbata is likely to be a dysfunctional response to damage in its invasive range, with little possibility of developing into a mutualism.

The spread of the Argentine ant: environmental determinants and impacts on native ant communities

The increasing numbers of invasive species have stimulated the study of the underlying causes promoting the establishment and spread of exotic species. We tracked the spread of the highly invasive Argentine ant (Linepithema humile) along an environmental and habitat gradient on the northeastern Iberian Peninsula to determine the role of climatic, habitat and biotic variables on the rate of spread, and examine impact on native ant communities. We found the species well-established within natural environments. The mean annual rate of spread of the invasion (7.94 ± 2.99 m/year) was relatively low compared to other studies, suggesting that resistance posed by native ants in natural environments with no or low human disturbance might delay (although not prevent) the spread of the invasion irrespectively of the land-use type. Factors related to the distance to urban areas and characteristics of native and introduced populations explained the rate of spread of the invasion, while habitat-related variables determined the distribution of native ants and the impact of the Argentine ant on them. Native ant communities became more homogeneous following the invasion due to the decline of species richness and abundance. Only few species (Plagiolepis pygmaea and Temnothorax spp.) were able to cope with the spread of the invasion, and were possibly favored by the local extinction of other ant species. Taken together, our results indicate that land uses per se do not directly affect the spread of L. humile, but influence its invasive success by molding the configuration of native ant communities and the abiotic suitability of the site.

Sib‐mating in the ant Plagiolepis pygmaea: adaptative inbreeding?

Multiple functional queens in a colony (polygyny) and multiple mating by queens (polyandry) in social insects challenge kin selection, because they dilute inclusive fitness benefits from helping. Colonies of the ant Plagiolepis pygmaea brash contain several hundreds of multiply mated queens. Yet, within-colony relatedness remains unexpectedly high. This stems from low male dispersal, extensive mating among relatives and adoption of young queens in the natal colony. We investigated whether inbreeding results from workers expelling foreign males, and/or from preferential mating between related partners. Our data show that workers actively repel unrelated males entering their colony, and that queens preferentially mate with related males. These results are consistent with inclusive fitness being a driving force for inbreeding: by preventing outbreeding, workers reduce erosion of relatedness within colonies due to polygyny and polyandry. That virgin queens mate preferentially with related males could result from a long history of inbreeding, which is expected to reduce depression in species with regular sibmating.

Seasonal nestmate recognition in the polydomous ant Plagiolepis pygmaea

Nestmate recognition cues can derive from genetic and/or environmental factors and can be contextdependent rather than fixed over time. We examined the influence of genetic relatedness and environment on nestmate recognition and its seasonal variations in a natural population of the polydomous (multiple-nests per colony) ant Plagiolepis pygmaea in southern France. Recognition between colonies was measured by testing aggression levels during encounters between five workers of colony A and one of colony B and vice versa. The combination of genetic data, spatial data and aggressive behaviour data shows that nestmate recognition cues have principally a genetic component. Whereas workers from different nests of the same colony are never aggressive to each other, they are always hostile to alien conspecifics regardless of the spatial or genetic distance between the colonies. Our results also reveal significant seasonal variations in the levels of aggression among workers of different colonies, probably according to the biological cycles of the species. Surprisingly, despite the mode of colony reproduction being budding in P. pygmaea, the population of Tarabel is not genetically structured.

Competition trade‐offs in the organisation of a Mediterranean ant assemblage

Abstract 1. The organisation of an ant assemblage inhabiting an olive orchard in central Italy was analysed and patterns of dominance among ant species were described in order to assess (i) the relationship between thermal dependency and degree of behavioural dominance, and (ii) the relationship between dominance and discovery ability.2. Activity patterns of the most abundant species on trees were examined in a sample of 120 trees during spring and summer. The degree of behavioural dominance and the ability of different species to discover new food sources were assessed using tuna baiting on a subset of 80 trees.3. Different ant species showed contrasting patterns of activity. Some species (such as Lasius lasioides, Camponotus lateralis, and Camponotus piceus) were most active during the warmer part of the day, while others restricted their activity to the cooler hours (Camponotus aethiops and Plagiolepis pygmaea). Some species (such as Crematogaster scutellaris) were active irrespective of the time of day.4. No clear relationship was observed between temperature of maximal activity and degree of behavioural dominance. There was, however, a positive relationship between behavioural dominance and thermal range of activity. A positive relationship between dominance and ability to find resources, with the most behaviourally dominant and aggressive species being most efficient in finding food items, was also observed.5. The results support the idea that the temperature–dominance relationship is much more complex in Mediterranean‐type habitats than in other ecosystems. Of particular interest is the positive dominance–discovery relationship. This finding contrasts with previous investigations, which reported a negative relationship between dominance and discovery ability and suggested that this pattern plays a role in promoting the coexistence of species in ant communities.

Mating for convenience or genetic diversity? Mating patterns in the polygynous ant Plagiolepis pygmaea

Several genetic and nongenetic benefits have been proposed to explain multiple mating (polyandry) in animals, to compensate for costs associated with obtaining additional mates. The most prominent hypotheses stress the benefits of increased genetic diversity. In social insects, queens of most species mate only once or have effective mating frequencies close to one. Yet, in a few species of ants, bees, and wasps, polyandry is the rule. In these species, colonies are usually headed by a single queen, whereas multiple queening adds diversity in several of the remaining species, especially in ants. Here we investigated mating frequency, inbreeding and relatedness between the queens and their mates in the polygynous ant Plagiolepis pygmaea, and the effect of polyandry on the genetic diversity as a function of the effective population size of individual colonies. Our results show that polyandry occurs frequently in the species. However, queens are frequently inseminated by close relatives, and additional sires add little genetic diversity among offspring of individual queens. In addition, the increase in diversity at the colony level is only marginal. Hence, contrary to established notions, polyandry in P. pygmaea seems not to be driven by substantial benefits of genetic diversity. Nonetheless, very small or as yet unidentified genetic benefits to one party (males, workers, queens) in conjunction with low costs of mating may favor polyandry. Alternatively, nongenetic factors, such as convenience polyandry, may be more important than genetic factors in promoting polyandry in P. pygmaea. © The Author 2006. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

Inbreeding and kinship in the antPlagiolepis pygmaea

In ants the presence of multiple reproductive queens (polygyny) decreases the relatedness among workers and the brood they rear, and subsequently dilutes their inclusive fitness benefits from helping. However, adoption of colony daughters, low male dispersal in conjunction with intranidal (within nest) mating and colony reproduction by budding may preserve local genetic differences, and slow down the erosion of relatedness. Reduced dispersal and intranidal mating may, however, also lead to detrimental effects owing to competition and inbreeding. We studied mating and dispersal patterns, and colony kinship in three populations of the polygynous ant Plagiolepis pygmaea using microsatellite markers. We found that the populations were genetically differentiated, but also a considerable degree of genetic structuring within populations. The genetic viscosity within populations can be attributed to few genetically homogeneous colony networks, which presumably have arisen through colony reproduction by budding. Hence, selection may act at different levels, the individuals, the colonies and colony networks. All populations were also significantly inbred (F=0.265) suggesting high frequencies of intranidal mating and low male dispersal. Consequently the mean regression relatedness among workers was significantly higher (r = 0.529-0.546) than would be expected under the typically reported number (5-35) of queens in nests of the species. Furthermore, new queens were mainly recruited from their natal or a neighbouring related colony. Finally, the effective number of queens coincided with that found upon excavation, suggesting low reproductive skew.

Evolution of miniaturisation in inquiline parasitic ants: Timing of male elimination in Plagiolepis pygmaea, the host of Plagiolepis xene

Inquiline ant species are workerless social parasites whose queens rely completely on the host worker force to raise their brood. A remarkable feature of inquiline ants is the small size of sexuals, which are of the same size as or smaller than host workers. It has been suggested that miniaturisation evolved by parasites to prevent host workers from discriminating between their own worker brood and the inquiline sexuals, so that male and female inquilines can develop under conditions where the host species does not produce its own sexuals. In line with the miniaturisation hypothesis, workers of the ant P. pygmaea cull all the male brood of their own species, whereas at the same time males of their inquiline parasite P. xene are reared to adulthood. Here, we tested whether P. pygmaea workers recognize and eliminate males of their own species when they reach the size of the larger workers. Contrary to the assumption that size is indeed the primary cue used by workers to discriminate male from worker brood, we found that males of P. pygmaea are culled between the small and medium larval stages, that is much before reaching the critical size of the largest worker larvae. Based on this finding, we propose an extension of the miniaturisation hypothesis with a first step whereby the parasitic P. xene males escape the caste and sex recognition system of the host during early development. The most likely mechanism is chemical mimicry of host worker larvae. Miniaturisation would have evolved later to prevent the host workers to secondarily use size as a recognition cue to eliminate P. xene males.

Community structure of ground-ants: the role of single trees in a Mediterranean pastureland

Abstract A study was carried out to determine the effect of single tree (Quercus ilex subsp, ballota) shaded microhabitats on the community structure of ground-nesting ants in a semi-natural Mediterranean ecosystem (“dehesa”). A total of 1156 ant nests belonging to 20 species were detected in the study area, with a mean density of 10–11 nests per 100 m2. Ground ant nests were denser under tree cover than on exposed grassland. Species richness and diversity also tended to increase in areas under tree canopies. These effects were found to be proportional to the area of tree cover up to a certain limit, beyond which the trend became negative. Species composition differed between open ground and tree-shaded microhabitats. Shade-tolerant species such as Plagiolepis pygmaea were more common near trees, whereas the seed harvester ant Messor barbarus was more common in open areas.

Social parasitism in ants: effects of the inquiline parasite Plagiolepis xene St. on queen distribution and worker production of its host Plagiolepis pygmaea Latr.

The ant Plagiolepis pygmaea forms polygynous (several mated queens per colony) and polydomous (multiple nests per colony) colonies that may be parasitized by the workerless social parasite Plagiolepis xene. Earlier laboratory experiments showed that P. xene strongly restricts host worker production (Passera, 1972); however, this negative effect seems not to occur under natural conditions. Here, we explored the hypothesis that, in infested natural colonies of P. pygmaea, parasite queens affect the distribution of the host queens resulting in the latter inhabiting unparasitized nests of the colony at the period of egg-laying. Our field studies show that the presence of the inquiline ant P. xene influences host queen distribution, with a higher level of dispersion within parasitized colonies. In winter, there is a positive association between the number of host queens and the number of parasites in queenright nests. Such a relationship does not occur in summer, so that when egg-laying reaches its maximum activity most queens of the host are found in unparasitized nests. Moreover, the proportion of queenright nests parasitized was dramatically lower than in the winter. A detailed comparison of worker production between parasitized and unparasitized field colonies reveals no difference. Experiments show that reduced worker production in parasitized nests reared under laboratory conditions results from oophagy by the parasitic queens. Overall, our data suggest that the segregation of the host and parasite queens in different nests at the time of egg-laying results in part from host queens avoiding inhabiting parasitized nests to reduce oophagy by the parasite. We discuss the behavioral and ecological implications of our findings.