Sociobiology: Volume 59, Number 2, 2012

Feature Articles:


Two New Species of Stenamma (Hymenoptera: Formicidae) from Indian Himalaya With a Revised Key to the Palaearctic and Oriental Species

By Himender Bharti, Irfan Gul & Yash Paul Sharma

ABSTRACT

Two new species of genus Stenamma viz Stenamma wilsoni sp. nov. and Stenamma jhitingriense sp. nov. are described from Indian Himalaya. This adds two more species to the genus from Indian Himalaya, with only Stenamma kashmirense Baroni Urbani, 1977 described earlier. A revised key to 26 species from Palaearctic and Oriental is provided here with.

KEY WORDS: Stenamma, Taxonomy, Myrmicinae, Ants, New species, Key, Indian Himalaya

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Gaoligongidris planodorsa, a New Genus and Species of the Ant Subfamily Myrmicinae from China with a Key to the Genera of Stenammini of the World (Hymenoptera: Formicidae)

By Zheng-Hui Xu

ABSTRACT

A new genus and species of the ant subfamily Myrmicinae collected from the Gaoligong Mountain Nature Reserve of the Hengduan Mountains, southwestern China, is described. The new genus, Gaoligongidris gen. nov., is close to Lasiomyrma Terayama & Yamane, but with anterior clypeal margin not angled, metanotal groove deeply impressed, propodeal spiracles large, propodeal spines long and slender, and petiolar peduncle longer than the node. The new genus is distributed in the Oriental region and belongs to the tribe Stenammini of Myrmicinae. A key to the known genera of Stenammini of the world based on worker and queen castes is provided.

KEY WORDS: Hymenoptera, Formicidae, Myrmicinae, Gaoligongidris, New genus, China

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Aspartame-based Sweetener as a Strong Ant Poison: Falsifying an Urban Legend?

By Jouni Sorvari & Marja-Katariina Haatanen

ABSTRACT

Information about the usability of artificial sweeteners, mainly aspartame, for controlling pest ants has spread widely in the internet. With a laboratory experiment we tested the effect of an aspartame based sweetener on the mortality of the black garden ant Lasius niger, a common pest ant in kitchens in Europe. The aspartame-based sweetener was added to the laboratory jelly food of ants in the experimental group (16 colonies). The control group (14 colonies) received otherwise similar jelly but without the aspartame-based sweetener. During the 35 day period of experiment we did not find any signs of aspartame induced mortality in tested ants. In addition, 135 colony founding L. niger queens were submerged in a sweetener solution (artificial sweetener + distilled water) and 135 queens were submerged in distilled water (control). The overall mortality was very low (<1.5%) and no between-group differences in mortality were found within 24 and 96 hours. Our results strongly oppose the rumors that aspartame sweeteners are effective as an ant poison, at least with a typical dose of household aspartame products.

KEY WORDS: ants, artificial sweetener, black garden ant, hoax, Lasius niger, pest control

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Temperature Influence on Species Co-Occurrence Patterns in Treefall Gap and Dense Forest Ant Communities in a Terra-Firme Forest of Central Amazon, Brazil

By Wesley Dáttilo and Thiago J. Izzo

ABSTRACT

In this study we evaluated the influence of temperature and species co-occurrence on the structure of an ant community of treefall gaps and surrounding dense forests in a terra-firme forest of Central Amazon, Brazil. For this, we collected ants at different hours, and at the time of each collection we measured the temperature of the environment. Even with the difference in the temperature variation and variation throughout the day, there was no difference in the richness and abundance of ants among the environments. Also, the ant species are distributed randomly and independently of one another in both studied environments in accordance with a null model (C-score). However, although not influenced by temperature, the ant composition of treefall gaps was different from the ant community of the surrounding dense forest. Possibly the composition and ant foraging in environments of treefall gaps and surrounding dense forests are not only influenced by temperature, but also by the interaction of this factor with the structural complexity of vegetation in terms of sites available for nesting and feeding, and other microclimatic factors. This generates a difference in ant composition of both environments. In addition, the structuring of ant community in tropical rain forests may actually be stochastic or neutral within each environment.

KEY WORDS: Tropical Rain Forest; Formicidae; Microclimatic factors; Competition; Diversity

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Analysis of Mortality in Africanized Honey Bee Colonies with High Levels of Infestation by Varroa destructor

By Igor Médici de Mattos & José Chaud-Netto

ABSTRACT

The mite Varroa destructor (Anderson & Treuman 2000) is one of the world’s most important plagues of apiculture. In Brazil this mite does not encounter good conditions for parasitism because weather conditions are not ideal for its maintenance, and some strains of Africanized honey bees are resistant to the parasite. This status is reflected in the low number of dead colonies caused by varroatosis and also the stability of infestation levels. The aim of this study was to evaluate the damage caused by mite infestations in hives with higher levels of infestation than the ones considered normal for Brazilian apiaries. The level of infestation in each colony was determined and the mortality rates of parasitized bees during development were periodically recorded. The G Test of Independence and a Test of Proportions were used to compare the data. The rates of mortality of pupae and larvae were mostly proportional to the level of infestation in each colony. All colonies showed mortality rates significantly higher than the control one. In Africanized honeybee colonies with high rates of infestation by Varroa destructor mortality rates varied from 19.27% to 23.28% in pupae (x̄ = 21.27%) and from 15.71% to 16.15% in larvae (x̄ = 15.93%), against 3.85% and 3.74% in the control colony, respectively. In the parasitized colonies the average rates of mortality caused by the hurtful effects of the mite were, respectively, 5.52 and 4.26 times greater in those two developmental stages. Thus it can be concluded that even in tropical regions, like Brazil, it is necessary to give special attention to the levels of mite infestation (IR), particularly where the IR tends to be higher.

KEY WORDS: Africanized honeybees, Apis mellifera, Varroa destructor, mortality analysis, development

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Effect of Temperature and Humidity on Survival of Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae)

By B. A. Wiltz

ABSTRACT

Two subterranean termite species were subjected to combinations of six temperatures (10°, 15°, 20°, 25°, 30°, or 35°C) and five relative humidities (RH) (55, 65, 75, 85, or 99%) to determine optimum conditions for survival. When small groups of the Formosan subterranean termite Coptotermes formosanus Shiraki or the eastern subterranean termite Reticulitermes flavipes (Kollar) were exposed to all 30 combinations of temperature and RH, survival times were significantly influenced by temperature, RH, and their interaction. For both species, survival times were longest at low temperatures and high RH. Maximum survival of small groups of C. formosanus and R. flavipes workers and soldiers occurred at the combination of 10°C and 99% RH C (LT50= 28.2 d, LT50 = 18.1 d, respectively). Survival of paired C. formosanus dealates was evaluated at combinations of 20°, 25°, or 30°C and 55, 65, 75, 85, or 99% RH. Survival was strongly influenced by temperature and humidity. Longest survival times until 50% mortality occurred at 99% RH and 20° or 25°C (LT50= 2.5 d, LT50 = 3.0 d, respectively). At all temperatures, mortality occurred too quickly for LT50 values to be determined when RH was 55% or 65%.

KEY WORDS:

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Influence of Pollen on the Development of Africanized Bee Colonies (Hymenoptera: Apidae)

By Anna Frida Hatsue Modro, Luís Carlos Marchini, Augusta Carolina de Camargo Carmello Moreti & Emanuel Maia

ABSTRACT

This study aimed to assess the importance of quality and quantity of pollen on the development of colonies in different seasons. The field experiment was conducted at the Apiary of the Department of Entomology and Acarology of Luiz de Queiroz College of Agriculture, using five beehives of A. mellifera. In order to characterize the quality of pollen, researchers considered measures of total dry mass (g) and the physical-chemical and pollen composition of pollen load and bee bread samples. The development of hives was assessed according to the area covered by pollen, honey, and brood population in the hive (cm²), as well as fluctuating asymmetry of worker bee wings. Spearman’s correlation was calculated among the assessed parameters. The value of ether extract of pollen loads was the only component that was related to the development of hives, its value increased as the area occupied by pollen in the hive decreased (-0.3200*), and as the difference of the number of hamuli of right and left hind wings increased (0.3317*). There was a positive relationship between the wealth (0.3150*) and evenness (0.3019*) of pollen composition and the size of brood population inside the hive. It was concluded that the development of the colony, mainly considering the area occupied by brood, is more successful with increased quantity, wealth, and evenness of collected pollen.

KEY WORDS: Apis mellifera, fluctuating asymmetry, physical-chemical composition, bee nutrition, bee pollen

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Trigona branneri (Hymenoptera: Apidae) as a Collector of Honeydew from Aethalion reticulatum (Hemiptera: Aethalionidae) on Bauhinia forficata (Fabaceae: Caesalpinoideae) in a Brazilian Savanna

By Gudryan Jackson Barônio, Ana Carolina Vieira Pires & Camila Aoki

ABSTRACT

The presence of aggregates of A. reticulatum on Bauhinia has been reported, but the insects were mainly attended by ants of the genus Camponotus, and stingless bees were not regularly recorded in aggregations. We observed a colony of thetreehopper A. reticulatum and stingless bees, Trigona branneri, interacting on Bauhinia forficata (Fabaceae). Agonistic behavior was observed in bees when another individual of the same species or ants approached. Although this is not proof that the interaction between stingless bees and treehoppers is mutualistic, the interactions between ants and this insect are common and mutualistic. Thus, if T. branneri effectively provides protection for the aphids, a new mutualism can be the focus of future research to determine if the bee-aphid interactions have same ecological functions as the ant-aphid interactions.

KEY WORDS: Ant-aphid interaction, Camponotus, trophobiosis, stingless bees, hemipterans

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A New Case of Ants Nesting within Branches of a Fig Tree: the Case of Ficus subpisocarpa in Taiwan

By A. Bain, B. Chantarasuwan, L.S. Chou, M. Hossaert McKey, B. Schatz & F. Kjellberg

ABSTRACT

Ficus is one of many plant genera involved in interactions with ants. The interaction is however little documented. We show here that ants, belonging mainly to the genus Crematogaster, nest in hollow internodes of young branches of Ficus subpisocarpa, a monoecious fig species studied in Taiwan. The ants feed on the mutualistic fig-pollinating wasps as well as on parasitic non-pollinating fig wasps. Nevertheless fig-wasps may not constitute a sufficient food source to ensure permanent presence of ants on the tree as the ants were observed to be frequently associated with hemipterans such as coccids and aphids. Fig wasps seem to constitute a reliable and sufficient food source on some dioecious Ficus species. On the contrary, in monoecious Ficus species, resident ants have always been observed to tend homopteran in addition to feeding on fig wasps. Frequent fruiting, prolonged fruit ripening period, ramiflory and rapid growth could constitute traits facilitating strong association based on fig-wasps' consumption of the monoecious F. subpisocarpa with ants. Despite these traits, ants were observed to tend hemipterans, and F. subpisocarpa does not seem to have evolved specialized morphological traits to facilitate the association.

KEY WORDS: ant-plant interaction, community ecology, Asian biodiversity, myrmecophytism, ant foraging

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How Do Scale Insects Settle into the Nests of Plant-Ants on Macaranga Myrmecophytes? Dispersal by Wind and Selection by Plant-Ants

By Chihiro Handa, Shouhei Ueda, Hirotaka Tanaka, Takao Itino & Takao Itioka

ABSTRACT

This report elucidates the process of settlement by Coccus scale insects into Crematogaster plant-ant nests formed inside the hollow stems of a myrmecophytic species, Macaranga bancana, in a tropical rain forest. We collected wafting scale insect nymphs from the canopy using sticky traps and characterized the DNA sequence of the trapped nymphs. In addition, we experimentally introduced first-instar nymphs of both symbiotic and nonsymbiotic scale insects to M. bancana seedlings with newly formed plant-ant colonies. Nymphs of symbiotic species were generally carried by ants into their nests within a few minutes of introduction. Most nymphs of nonsymbiotic species were thrown to the ground by ants. Our results suggest that in Crematogaster–Macaranga myrmecophytism, symbiotic coccids disperse by wind onto host plant seedlings at the nymphal stage, and plant-ants actively carry the nymphs landing on seedlings into their nests in discrimination from nonsymbiotic scale insects.

KEY WORDS: ant-plant, ant–hemipteran interaction, mutualism, Southeast Asian tropical rain forest, Borneo

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Nutritional and Temporal Effects on Hypopharyngeal Glands of Africanized Honeybees (Hymenoptera – Apidae)

By Fábio de Assis Pinto, Renata Oliveira de Fernades, Júlio César Melo Poderoso, Weyder Cristiano Santana, & Dejair Message

ABSTRACT

The hypopharyngeal gland (HG), along with the mandibular gland from Apis mellifera workers plays a fundamental role on the development of the hive. The protein based substances produced by the hypopharyngeal and mandibular glands are two important component of the royal jelly, which is responsible for caste differentiation and used to feed larvae, drones and the queen. Several factors may alter the physiology of glandular structures in honeybees and consequently their role within the beehive, and one of the most important factors is their nutritional status. However, few studies have evaluated the development of HG against different diets on Africanized honeybees. Our experiment was composed of four diets (treatments) offered to different groups of workers: (T1) honey, (T2) honey + soybean extract, (T3) honey + pollen and (T4) sucrose solution. The development of the glands was evaluated in two periods: 7 and 10 days of exposure to the diet types. According to the results, an interference of the diet on the acini area of the HG was observed. Bees that were fed with the sucrose solution or soybean extract presented the smallest acini areas as compared to the other treatments. The time of exposure to the different types of diets also had an effect on acini areas. Worker bees fed with honey and soybean extract for 10 days presented smaller acini areas when compared to bees dissected at the 7th day of exposure to those same diet types. Nevertheless, we also observed that factors other than just nutrition are important to the full development of the HG, such as the stimulus promoted by the young breeds.

KEY WORDS: nutrition, hypopharyngeal glands, pollen, Apis mellifera, royal jelly

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Nidification of Polybia platycephala and Polistes versicolor (Hymenoptera: Vespidae) on Plants of Musa spp. in Minas Gerais State, Brazil

By F.A. Rodríguez, L.C. Barros, P. Caroline, M.M. Souza, J.E. Serrão & J.C. Zanuncio

ABSTRACT

Social wasps are natural enemies of caterpillars and, therefore, they have potential to control insect pests in various crops. Three colonies of Polybia platycephala (Richards) and one of Polistes versicolor (Olivier) (Hymenoptera: Vespidae) were found on plants of banana (Musa spp.) in Minas Gerais State, Brazil. These colonies were at 3.50 m high, under the leaves, which provide shelter from environmental stress.

KEY WORDS:Banana, biological control, nest, pest, social wasps

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Aggregation Behavior in Spiderlings: a Strategy for Increasing Life Expectancy in Latrodectus geometricus (Araneae: Theridiidae)

By Ingrid de Carvalho Guimarães; Hermano Marques da Silva & William Fernando Antonialli Junior

ABSTRACT

Studies on the biology of Latrodectus geometricus are scarce, especially on the behavior and life expectancy of the species. In this study we investigated the importance of the aggregation behavior of juveniles on life expectancy and longevity of the species. Egg sacs were collected in the urban area of Dourados-MS and transferred to the laboratory. The spiderlings hatched were separated into two groups: spiderlings aggregated and isolated, kept in the presence of luminosity. The same tests were run with egg sacs deprived of luminosity. A calculation of entropy was performed for all cases. Individuals grouped held under light exposure showed 14.3 days of life expectancy and 46 maximum longevity and 14.8 days of life expectancy and 32 days of longevity when isolated. For individuals grouped and deprived of light life expectancy was 29.8 days and maximum longevity 85 days and 19.3 days of life expectancy and 26 days of maximum longevity when isolated. The entropy of individuals kept in the presence of light, when grouped was H = 0.692 and when isolated H = 0.377. For individuals deprived of light, the entropy was H = 0.628 when kept grouped and H = 0.143 when isolated. Therefore it is concluded that the aggregation behavior and luminosity influence the longevity and life expectancy of spiderlings. Cannibalism must be a strategy to acquire food reserves contributing to the survival of a small number of individuals.

KEY WORDS: Hourglass spider, cannibalism, survival

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Furcotanilla, a New Genus of the Ant Subfamily Leptanillinae from China with Descriptions of Two New Species of Protanilla and P. rafflesi Taylor (Hymenoptera: Formicidae)

By Zheng-Hui Xu

ABSTRACT

A new genus of the ant subfamily Leptanillinae, Furcotanilla gen. nov., discovered in southwestern China is described. The new genus is distributed in the Oriental region and belongs to the tribe Anomalomyrmini of Leptanillinae. A key to the 4 known genera of Leptanillinae of the world based on the worker caste is provided. Two new species of Protanilla collected from southwestern China, P. gengma sp. nov. and P. tibeta sp. nov., are described. The type-species of Protanilla, P. rafflesi Taylor, is also described based on the AntWeb images. A key to the 7 known species of Protanilla of the world based on worker and queen castes is prepared.

KEY WORDS: Hymenoptera, Formicidae, Leptanillinae, Furcotanilla, New genus, New species

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Field Activity of Reticulitermes grassei (Isoptera: Rhinotermitidae) in Oak Forests of the Southern Iberian Peninsula

By Ana M. Cárdenas, Lourdes Moyano, Patricia Gallardo & Juan M. Hidalgo

ABSTRACT

This paper presents preliminary data on the field activity of Reticulitermes grassei Clément in oak forests of the southern Iberian Peninsula. Recent research has provided information on the nature and intensity of termite damage to cork oaks (Quercus suber, L.) in northern Andalusia (Spain). Taking that information into account, the present study sought to determine annual field activity pattern in R. grassei, with a view to identifying more precisely the best time for applying control techniques. Data were obtained from field monitoring experiments conducted over a complete one-year cycle using termite-specific baited traps. Results for relative termite numbers at different periods indicated that forest activity was most intense in mid-summer, whilst the surface foraging area was greatest from late summer to early fall, peaking after the first autumnal rains. The findings of this study may help to enhance the efficacy of termite bait treatments in natural environments, since baits decay and lose effectiveness over time, and are also dispersed by the termites themselves. Accurate information on peak termite activity periods would enable products to be applied in most favorable timing, thus optimizing the results of treatment.

KEY WORDS: Field activity, Iberian Peninsula, Quercus suber, Reticulitermes grassei, Rhinotermitidae

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Trajectory of Water- and Fat-Soluble Dyes in the Grass-Cutting ant Atta capiguara (Hymenoptera, Formicidae): Evaluation of Infrabuccal Cavity, Post-Pharyngeal Glands and Gaster

By Luiz Carlos Forti, Marcílio de Souza Silva, Ricardo Toshio Fujihara, Nádia Caldato & Marise Grecca Garcia

ABSTRACT

The diet of leaf-cutting ants is based on cultivation of their symbiotic fungus, whose successful cultivation depends on the task of incorporation and handling of vegetable substrate. This task may cause the workers to be contaminated with toxic substances and thus decrease the survival of the colony. The objective of this study was to analyze the contamination of workers of Atta capiguara as well as the dissemination trajectory of water- and fat-soluble substances. Four colonies received non-toxic baits containing water-soluble dye Rhodamine-B and three, non-toxic baits with fat-soluble dye Sudan III. The dye Rhodamine-B stained the gaster in 40.31% of workers and showed no significant difference among castes. The Sudan III stained the infrabuccal cavity in 35.41%, post-pharyngeal glands of 24.22% and gaster in only 8.44% of the workers, with no significant difference among the castes. The water-soluble dye was spread in the body of workers through the digestive system while fat-soluble dye was diverted to the post-pharyngeal glands.

KEY WORDS: digestive system; glands; leaf-cutting ants; manipulation; toxic baits

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Effect of Soil Water Content on Toxicity of Fipronil Against Solenopsis invicta

By Jie Wang, Qi Yang, Haixiang Huang, He Zhang, Juan Hu & Yijuan Xu

ABSTRACT

This study evaluated the effect of Fipronil on the survival of fire ant workers with different doses and soil water contents and further examined the persistent effect of the same dose of powder at 10%, 50% and 90% soil water content. The results showed that mortality was positively correlated to the dosage. This result indicated that the survival rates of workers treated by powder at different RSW (Relative soil water content) were significantly different (P < 0.01). At the RSW of 10% and 20%, the survival rates of workers were 40.67 and 49.00 respectively, which showed no obvious difference from other treatments but were lower than the control. The survival rate decreased sharply when the RSW was 90%, and was obviously lower than that of treatments at moderate (30-50%) RSW. The contact powder showed worst persistent effect when the soil water content was 10%, but at the soil water content of 50% and 90%, the lethal effect of the powder was higher and was more persistent.

KEY WORDS: Solenopsis invicta, Contact powder, Soil water content, Mortality rate, Persistent effect

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Performance of AltrisetTM (Chlorantraniliprole) Termiticide Against Formosan Subterranean Termites, Coptotermes formosanus Shiraki, in Laboratory Feeding Cessation and Collateral Transfer Trials, and Field Applications

By Robert T. Puckett, T. Chris Keefer, & Roger E. Gold

ABSTRACT

Chlorantraniliprole represents the first compound to be registered as a termiticide by the Environmental Protection Agency (EPA) in over a decade. This novel termiticide is currently registered as a ‘reduced-risk pesticide’ by the EPA. Laboratory and field trials were conducted to quantify mortality of Formosan subterranean termites (FST), Coptotermes formosanus Shiraki resulting from chlorantraniliprole treated soil, the degree to which the termites curtail feeding intensity post-exposure to chlorantraniliprole treated soil, collateral transfer of chlorantraniliprole among nest mates, and the effectiveness of chlorantraniliprole as a remedial treatment against structural infestations of FST. Termites which were exposed to chlorantraniliprole treated soil consumed significantly less paper than unexposed FST. The mean percent mortality of those termites exposed to chlorantraniliprole treated soil was significantly greater than that of unexposed FST. Depending on donor:recipient ratios, the mean mortality of recipients ranged from 14.65 – 90.00 % in the collateral transfer trials. There was a positive correlation between increased donor density and recipient mortality. Through 24 mo post-treatment, 27.3% of the structures which were treated in field trials were observed to have infestations of termites that required re-treatment; however, no FST were observed during the 30 and 36 month post-treatment inspections. Additionally, a novel scoring rubric was developed that will allow standardization of field study sites with respect to dissimilarity in site variables, and will allow for more consistent comparison of results across disparate field experiments. An explanation for the lack of successful remediation of many of the structures involved in the field trial is proposed and is based on our novel scoring system.

KEY WORDS: Coptotermes, Chlorantraniliprole, Termiticide, Reduced-Risk, Invasive Species

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Influence of Cave Size and Presence of Bat Guano on Ant Visitation

By Wesley Dáttilo, Ricardo E. Vicente, Rafael V. Nunes2 & Rodrigo M. Feitosa

ABSTRACT

This is the first study which evaluated the influence of cave size and presence of bat guano in ant visitation in Brazilian caves. We provide a list of the ants associated with 27 caves in northeastern Brazil, an area situated in the transition between Cerrado (Brazilian savanna) and Amazon Domain. The study was conducted between January and August 2010. We recorded 24 ant species inserted into 12 genera, 10 tribes, and six subfamilies. The size of the cave and the presence of guano did not influence the richness of ants, and most of the caves had single species. Camponotus atriceps was the species with the larger distribution, being collected in five caves. In addition, we discuss geographic distribution of records and possible ecological roles of ants in cave environments.

KEY WORDS: Biospeleology, Cavernicolous; Competition; Invertebrates

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Natural Biological Control of Diaphania spp. (Lepidoptera: Crambidae) by Social Wasps

By Paulo Antônio Santana Júnior, Alfredo Henrique Rocha Gonring, Marcelo Coutinho Picanço, Rodrigo Soares Ramos, Júlio Cláudio Martins & Dalton de Oliveira Ferreira

ABSTRACT

The social wasps (Hymenoptera: Vespidae) are important agents of biological control for agricultural pests. Diaphania hyalinata L. and Diaphania nitidalis Cramer (Lepidoptera: Crambidae) are among the main pests of plants in the Cucurbitaceae family. Although the importance of social wasps is acknowledged, little is known about their activity as biological control agents in Diaphania spp. Thus, this work aimed to study the natural biological control of the caterpillars D. hyalinata and D. nitidalis by social wasps. We studied the natural biological control of caterpillars of D. hyalinata and D. nitidalis on cucumber hybrids Sprint 440 II and Vlasstar. The main predators of Diaphania caterpillars were the social wasps, followed by Diptera: Syrphidae; Hemiptera: Anthocoridae; Coleoptera: Coccinellidae, Anthicidae; Neuroptera: Chrysopidae and Arachnida: Araneae. Predation of D. hyalinata caterpillars by social wasps was high from the second to fifth instar. The predation of D. nitidalis caterpillars by social wasps was high from the second to fourth instar. There was no predation by social wasps on the first instar larvae of Diaphania spp. The cucumber hybrids did not influence the predation of Diaphania spp. by social wasps. The main social wasp predator of Diaphania spp. was Polybia ignobilis (Haliday). Also, we observed the social wasp Polybia scutellaris (White) preying on D. hyalinata but at low intensity.

KEY WORDS: Social insects, Vespidae, Diaphania hyalinata, Diaphania nitidalis, Cucurbitaceae, predators

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The Effects of Temperature on the Foraging Activity of Red Imported Fire Ant Workers (Hymenoptera: Formicidae) in South China

By Yong-yue Lu, Lei Wang, Ling Zeng & Yi-juan Xu

ABSTRACT

In this study, we investigated the effects of temperature of the ambient air, ground surface, and the soil at 5-cm deep on the foraging activity of the workers of red imported fire ant, Solenopsis invicta Buren, in South China with the method of bait traps. Significant correlations were observed between the temperature and the foraging activity of fire ants. Specifically, when the ambient temperature was above 20 °C, the fire ants foraged actively, and the activity reached a maximum when the ambient temperature was between 25 to 33 °C. But the foraging activity decreased as the ambient temperature rose higher than 34 °C. Moreover, fire ants were found to forage at maximal rates with the soil surface temperature between 27 to 40 °C. The ants started foraging when the soil temperature at 5-cm deep was between 16 to 48 °C, while 28~37 °C was the optimal temperature for the foraging activity. The extreme temperature thresholds for foraging of the ambient air, soil-surface, and soil at 5-cm deep were 11 °C/44 °C, 10 °C/57 °C, and 12 °C/48 °C respectively.

KEY WORDS:

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