Sociobiology: Volume 44, Number 1, 2004

Feature Articles:

Native and Exotic Ants of the Azores (Hymenoptera: Formicidae)

By James K. Wetterer, Xavier Espadaler, Andrea L. Wetterer, & Susana G. M. Cabral

ABSTRACT

The Azores, a North Atlantic archipelago, has 14 known ant species. Although some earlier researchers have regarded all ants in the Azores to be exotic, we believe several are native (i.e., predating human arrival). Five ant species found in relatively undisturbed environments and not widely distributed beyond the Azores, neighboring Madeira, and the Mediterranean, we judge to be native to the Azores: Hypoponera eduardi, Lasius grandis, Leptothorax unifasciatus, Monomorium carbonarium, and Plagiolepis schmitzii. In addition, Tetramorium caespitum, though widely distributed, shows variation within the Azores that suggests it is native. Six ant species found only in highly disturbed environments in the Azores and distributed around the world through human commerce, we consider exotic: Hypoponera punctatissima, Linepithema humile, Paratrechina longicornis, Pheidole megacephala, Tetramorium bicarinatum, and Tetramorium caldarium. In addition, Solenopsis (Diplorhoptrum) sp. of unknown taxonomic status, and Aphaenogaster senilis, which is not widely distributed, were restricted to disturbed sites and appear to be exotic. Five of the six native ant species (all except P. schmitzii), but only two of the eight exotic species (A. senilis and L. humile) are common and widespread in the Azores. The Argentine ant, L. humile, is the only exotic ant species that appears to have some impact on native species, but it was abundant only in scattered urban and agricultural areas. Three ant species that are important tropical pests, P. longicornis, P. megacephala, and T. bicarinatum, all have their highest latitude populations in the Azores, probably a reflection of the relatively mild climate due to the warming influence of the Gulf Stream. Relatively natural areas in the Azores have low ant species richness, but usually all the ants present are native. Urban sites often have higher ant species richness due to the presence of both native and exotic species. Thus, the total ant species richness is not a useful indicator of habitat integrity. The presence of exotic ant species, however, is an excellent indicator of disturbance. Twelve of the 14 recorded ant species (all except A. senilis and T. caespitum) in the Azores also occur in Madeira. The Azores have far fewer ant species than Madeira (27 species), no doubt related to the Azoresí younger age, higher latitude, and greater distance from continental source populations.

KEY WORDS: ants, Azores, exotic species, Linepithema humile, Macaronesia, native species

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Colony Genetic Structure of the Ant Camponotus ocreatus (Hymenoptera: Formicidae)

By Michael A.D. Goodisman & Daniel A. Hahn

ABSTRACT

An increasing number of studies have uncovered evidence of polygyny or polyandry in the ant genus Camponotus. To further increase our understanding of the sociobiology of ants in this genus, we used DNA microsatellite markers to analyze the genetic structure of C. ocreatus. We found that the genotypes of workers, gynes, and males in 15 of the 16 nests analyzed were consistent with having been produced by a single, once-mated queen. However, nestmate genotypes in one nest were more complex, signifying the presence of multiple reproductives. In addition, the adjusted estimate of diploid nestmate relatedness, r = 0.65, suggested infrequent polygyny or queen polyandry. We also uncovered some evidence of inbreeding between queens and their male mates, and occasional polydomy in this population. Overall our results indicate that the social structure of most C. ocreatus colonies is relatively simple, although the genetic structure of a few colonies suggests that more than a single queen and male may contribute to offspring production.

KEY WORDS:

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Distribution and Establishment of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in Alabama

By Xing Ping Hu & Faith Oi

ABSTRACT

Twelve counties in Alabama have been known to be infested by the Formosan subterranean termite, Coptotermes formosanus Shiraki, since its debut in Mobile in 1985. Records show that the infestations have occurred in and around structures or trees in residential areas, and most are associated with the introduction of used railroad crossties as landscaping timber. A couple cases are associated with construction timber obtained from Louisiana. A review of records also shows a clear pattern of the range expansion along main interstate highways, possibly indicating that the spread is aided by human transportation of infested materials. The two gulf coastal counties, Mobile and Baldwin, have the highest number of Formosan termite infestations and where its distribution should considered widespread posing a greater threat to consumers. In all inland counties, Formosan subterranean termite infestations occur sporadically, but the number of reported infestations increases each year. The northernmost record was an alate sample from the windowsill of a house in Jackson County (34º67íN, 86º03íW) in 1996, 325 miles inland. In 2003, a verified, established infestation was recorded in Cullman city (34º14íN, 86º51íW), 290 miles inland, where, in January 2003, the mean temperature was 2.11ºC, with a low of -15.00ºC. This infestation represents convincing evidence that C. formosanus can become well established in areas previously thought uninhabitable in Alabama. Despite the rapid range expansion, there has been no governmental effort to mitigate the spread of C. formosanus in Alabama. Coordination of a statewide Formosan subterranean termite control effort is needed.

KEY WORDS: Coptotermes formosanus, expansion range, Alabama

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Determining Factors of Arboreal Ant Mosaics in Cerrado Vegetation (Hymenoptera: Formicidae)

By Carla R. Ribas & José H. Schoereder

ABSTRACT

In this paper we tested the existence of arboreal ant mosaics in Cerrado (Brazilian savanna) vegetation and their causal processes. We tested the hypotheses that mosaics could be caused by distribution of resources and habitat conditions, against the null hypothesis that the spatial distribution of ants is caused by stochastic processes. The ants were sampled in seven 20x50m plots, using baited pitfalls and hand collecting. The existence of ant mosaics was assessed using association tests, and the presence of negative associations among dominant species confirmed the mosaic. Species co-occurrence was tested comparing randomized matrices with the observed co-occurrence matrix. The association of dominant species with resources (tree species) and habitat conditions (tree cover) was also tested. The results varied in each plot, showing that mosaic distribution may be caused by: (1) dominant species preference by specific habitat conditions, (2) competitive interactions and (3) stochastic processes. The occurrence of three different explanations to ant spatial distribution leads us to suggest that using only one hypothesis to explain ant mosaics is an oversimplification of the factors involved in this pattern. Probably ant mosaics appear as the result of a complex interaction of several biological and stochastic factors, which have to be formally tested, and not simply assumed.

KEY WORDS: community ecology, competition, Formicidae, species-specific relationships, stochastic processes

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Effects of Competing Food Sources on Subterranean Termite, Reticulitermes spp., (Isoptera: Rhinotermitidae), Consumption of Hexaflumuron Treated Baits in Laboratory Assays

By R.C. Perrott, D.M. Miller & D.E. Mullins

ABSTRACT

The impact of competing food resources on Subterranean termite consumption of [14C]hexaflumuron treated diets was compared in choice and no-choice tests. Consumption was quantified for groups of termites and individuals to determine if consumption by a single termite reflected that of the termite group. In no-choice tests groups of 100 termite workers consumed an average of 3 mg of [14C]hexaflumuron bait in 2d, and 11.4 mg in 5d. In the presence of a competing food resource, an [3H]inulin treated diet, consumption of the [14C]hexaflumuron diet was significantly reduced (0.2 mg) at 5d. Consumption comparisons of competing food resources in the choice tests were made to determine termite preference for particular food resources. In choice tests comparing [14C]hexaflumuron and [3H]inulin diets, consumption of the inulin diet was significantly greater (6.0 mg) than the hexaflumuron (0.2mg) at 5d, indicating a preference for the inulin treated diet. Quantification of radioactive isotopes from individual termites was used to estimate how much a single termite consumed of the [14C]hexaflumuron diet in the presence of a competing food source. Individual termite consumption was found to reflect the population consumption results. At 5d, [14C]hexaflumuron consumption was significantly reduced from 56.9µg in the no-choice test to only 19.3µg in the presence of a competing control diet. [14C]hexaflumuron consumption was further reduced to 2.3µg when competing with the [3H]inulin treated diet. Consumption comparisons of [14C]hexaflumuron and [3H]inulin in the choice tests indicated a significant preference for the inulin treated diet.

KEY WORDS: [14C]hexaflumuron, [3H]inulin, Reticulitermes spp., consumption

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Temperature and Humidity Tolerances of the Ghost Ant, Tapinoma melanocephalum (Hymenoptera: Formicidae)

By Arthur G. Appel, Julie P.-S. Na, & Chow-Yang Lee

ABSTRACT

Temperature and humidity tolerances of the ghost ant, Tapinoma melanocephalum (Fabricius) were examined in a series of laboratory experiments. LT50 values for worker ants ranged from 2.0 h at 45ºC and 97% RH to 43.7 h at 15ºC and 55% RH. Mean 24 h mortality ranged from 5.7 to 100% for 15ºC and 55% RH and 45ºC and 75% RH, respectively. At 97% RH, ghost ants tolerated the greatest range of temperatures, with 24 h mortality of <30% between 15 and 35ºC. The importance of temperature and humidity tolerance to ghost ants is compared with other urban insect pests of tropical origin.

KEY WORDS: Tapinoma melanocephalum, temperature tolerance, humidity tolerance

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Interspecific Variation in the Pupal-Wing Buds of Major Workers in the Ant Genus Pheidole (Hymenoptera: Formicidae)

By Shin-ya Sameshima, Toru Miura & Tadao Matsumoto

ABSTRACT

The ant genus Pheidole generally has dimorphic workers. Although both worker castes lack wings as adults, previous studies have shown that major-worker pupae have wing buds that disappear by the time of emergence, whereas minor-worker pupae do not. Here, we investigated interspecific variation in the presence of pupal-wing buds for five Pheidole species, and show that three of these species lack pupal-wing buds in major workers. This finding shows that the presence of pupal-wing buds in major workers is not ubiquitous for this genus. Further, regardless of the interspecific variation in the presence of pupal-wing buds, histological examinations showed that there were no interspecific differences in the size and form of larval-wing discs. This indicates that the interspecific variation in pupal-wing buds is due to developmental differences in the wing degeneration process at the prepupal stage. These differences of wing developmental processes may show the species-specific allometric features in the dimorphic workers.

KEY WORDS: Pheidole, pupal wing buds, worker dimorphism, caste differentiation

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Strategies on the Developmental Biology of Incipient Colonies of Coptotermes gestroi (Isoptera: Rhinotermitidae) in Different Substrates

By Marisa Vianna Ferraz & Eliana Marques Cancello

ABSTRACT

Coptotermes gestroi Wasmann (formerly C. havilandi Holmgren) is an oriental species of termite that has been introduced into Brazil. It is now the most destructive wood pest in Southeastern Brazil. The results of a study of couples of alates collected in swarmings and reared in the laboratory are reported. The study focused on the following aspects: the substrate choice by reproductive pairs, colony survival rate, preoviposition period, number and viability of eggs, incubation period, worker instars period, mortality rate of the worker instars, molting and percentage of soldiers. We also report a few behavioral observations. Success in the establishment of colonies in different substrates, including sand and filter paper, shows the high plasticity of this species and demonstrates that contact with soil is not necessary for the establishment of a colony.

KEY WORDS: developmental biology, incipient colonies, Coptotermes gestroi, Isoptera, pest species

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Reproductive Strategy of Coptotermes gestroi (Isoptera: Rhinotermitidae) in Brazil

By Ana Maria Costa-Leonardo & Alberto Arab

ABSTRACT

The termite Coptotermes gestroi (Wasmann) (Rhinotermitidae) is an exotic species in Brazil. This species forms colonies headed by primary reproductives, however, non-functional neotenics are commonly found even in the presence of the imaginal pair. The presence of non-functional neotenics in C. gestroi colonies may correspond to a strategy of this termite species for rapid colonization in foreign areas, instead of a response to chemical control methods.

KEY WORDS: subterranean termites, primary reproductives, nymphs, neotenics, replacement reproductives.

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Effects of the Desiccation Process on Survival and Food Consumption of Japanese Subterranean Termites (Isoptera; Rhinotermitidae), Reticulitermes speratus and Coptotermes formosanus

By Tomoe Nakayama, Tsuyoshi Yoshimura, & Yuji Imamura

ABSTRACT

Reticulitermes speratus (Kolbe) and Coptotermes formosanus Shiraki were used to evaluate the effect of desiccation process (different mass loss rates) on survival and food consumption. Among 9 temperature (20, 25, and 30ºC)- relative humidity (RH) (50, 70, and 90%RH) combinations without a water supply (desiccating condition), the longest survival periods obtained were 144 hours for R. speratus and 168 hours for C. formosanus at the 20ºC-90%RH condition, whereas the shortest survival periods were 24 hours for R. speratus and 36 hours for C. formosanus at the 30ºC-50%RH condition. After these two desiccation treatments, the lower survivals were observed in workers exposed to the 30ºC-50%RH condition for 8.5 hours (R. speratus) and 12 hours (C. formosanus) in the recovery process. On the other hand, significantly lower food consumptions were observed in both workers exposed to the 20ºC-90%RH condition after 4 weeksí recovery treatment. These results suggest that not only lethal mass loss from termite bodies but also desiccation process can affect survival and food consumption of Japanese subterranean termites.

KEY WORDS: Coptotermes formosanus, Reticulitermes speratus, desiccation, food consumption, survival.

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Decision-making Systems in Recruitment to Food for two Nasutitermitinae (Isoptera: Termitidae)

By Carmen Andara, Solange Issa, & Klaus Jaffé

ABSTRACT

Most termites use several different stable resources simultaneously using chemical mass recruitment systems to exploit new food sources. In the light of the decision-making system for recruitment (Democratic and Autocratic systems) described for ant species, this work studied the mass-recruitment system of the arboreal carton nest building termites N. ephratae and N. corniger. Our results show that these two species display recruiting dynamics that differ markedly from what was defined as ìDemocraticî decision making, conforming most closely to the antís ìAutocraticî system, where scouts control the absolute amount of pheromone deposited on a trail according to the quantity and quality of the food source. These termites, however, seem to have additional features, making the regulation of the dynamics of the recruitment process much more complex than that described for ants. This work represents the first observations on the decision-making system used by termite societies in chemical mass recruitment to a new food source.

KEY WORDS: Nasutitermes corniger, N. ephraetae, decision making, recruitment.

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Nest Micromorphology of the Termite Cortaritermes fulviceps in Different Types of Soil (Isoptera: Termitidae)

By Marcela Cosarinsky

ABSTRACT

The micromorphology of nests of Cortaritermes fulviceps (Isoptera, Termitidae) located in different types of soils is described using thin sections, following the methodology for studying soil micromorphology. In all these cases, the nest microstructure is remarkably different from that of the surrounding soil, indicating that workers modify the soil microstructure when building. In sandy soils, with scarce organic matter, workers employ single sand grains cemented with fecal material to build the nest. In loamy clay soils, very rich in organic matter, single sand grains and soil crumbs are also cemented with fecal material, whereas in silty soils, the nests are constructed with soil pellets molded in the buccal cavity of the workers, loaded and piled without any kind of mortar. The fecal origin of the cement was determined by a comparative analysis of its constituents with those of the workersí hindgut content.

KEY WORDS: termite nests, micromorphology, Cortaritermes fulviceps

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Recommendations for Treated-Area Choice Assays with Termites (Isoptera)

By Chris J. Peterson, Patrick D. Gerard, & Janice Ems-Wilson

ABSTRACT

The repellency of catnip (Nepeta cataria) essential oil was evaluated in a treated-area choice assay with subterranean termites (Reticulitermes spp.). It appeared that fewer R. virginicus were found on the treated portion of a Petri dish within a period of about 7 d; R. flavipes was not affected by the presence of the oil. The data collected from the control dishes, however, showed an unacceptably high Type I error rate (rejection of Ho: nt = nu, when Ho is true, where nt is the expected number of termites on the treated side and nu is the expected number of insects on the untreated side). The tendency of termites to cluster was the probable reason for this, and calls into question the data obtained from the tests. Computer simulations, using a range of cluster factors, replications and numbers of termites per replication, were conducted, and the Type I error rate was calculated when a cluster center (a point corresponding to a random angle θ and radius ρ value within a circle) and random ìtermiteî positions about the cluster center were plotted. Type I error rates were consistently inflated for all analyses that were based on individual animal behavior, and could not be corrected by increasing replications. We recommend an analysis where the number of insects on the treated or untreated side is recorded, then the dish is designated as ìrepelledî or ìnot repelled,î and the number of repelled dishes is analyzed. This method effectively controls the Type I error rate so that it is no greater than the nominal value. It is recommended to use at least 25 replications to ensure adequate statistical power. Analysis of these types of data is best accomplished by use of Fisherís Exact test or Boschlooís Exact Unconditional test.

KEY WORDS: Reticulitermes spp., choice-assay, repellent, clustering, analysis

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A Rapid Marking Technique for Reticulitermes flavipes (Isoptera: Rhinotermitidae)

By C.E. Long

ABSTRACT

Techniques for marking large numbers of termites typically rely on feeding workers filter paper impregnated with fat-soluble dyes. Using the traditional method of offering the termites slightly moistened, stained filter paper, Reticulitermes flavipes typically require 3-5 days of feeding on the paper to acquire sufficient coloration. By combining a ëfast markingí technique developed for Coptotermes and the phagostimulatory effect of a 1% glucose solution, a rapid marking technique was designed and tested for R. flavipes. Slightly desiccated workers were offered a high volume of relatively concentrated Neutral Red and Nile Blue dyes. The thirsty termites fully incorporated the dye and became distinctly colored in 48 and 60 hrs, respectively, with no significant reduction in survivorship or body weight after 3 weeks. This method successfully accelerated the traditional, 3-5 day marking period. The addition of a 1% glucose solution had no impact on termite survivorship, weight, dye uptake, or color retention.

KEY WORDS: Reticulitermes, fat-stains, mark-recapture

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A New Genus and Species of Staphylinidae (Coleoptera: Aleocharinae) That is a Probable Myrmecophile

By David H. Kistner

ABSTRACT

A new genus, Vertexprorogatio, is described from Sri Lanka with its generitype, Vertexprorogatio taprobanes. The species is a probable myrmecophile based on the structure of the antenna, legs, and the partially limuloid form of the body.

KEY WORDS: Vertexprorogatio taprobanes, Myrmedoniina, Sri Lanka

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