Fuminori Ito

• Ph.D.
• Professor at Kagawa University

Seasonal changes affect the distribution and behavior of animals. Ant societies are strongly affected by the dry season: they suffer from high temperatures and desiccation, but also from the lower availability of insect prey. However, some species of ants are involved in mutualistic relationships with myrmecophytic plants that provide a moist nesti...

Temporary social parasitism is the most common type among four types of social parasitism and is known from more than 200 ant species. Queens of temporary social parasites invade a host ant colony, kill the host queen, and use the host workers as a workforce during the colony founding stage. In our study, we collected seven mixed colonies consistin...

Queen ants of the Japanese ponerine genera are described, with the fi rst key to the Japanese genera based on the queen caste. Important queen characters are enumerated and caste diff erences are discussed for each genus. Physical and behavioral aspects of functional queens (alate/dealate queen, ergatoid, and gamergate) in the Japanese ponerines ar...

The ant species diversity in tropical Asia has been investigated in several locations, however, these studies mainly focused on well preserved forests or plantations. The ant fauna in urban parks has only been investigated in a limited number of locations in Singapore, Hong Kong, Macao, and Indonesia. We investigated the ant fauna in the Purwodadi...

The foraging and feeding behaviors were observed for the myrmicine ant Calyptomyrmex rectopilosus collected in northern Vietnam. C. rectopilosus was found to be a specialized predator on the arthropod eggs, and the queen fed on trophic eggs and engaged in oral trophallaxis with workers. Unlike Calyptomyrmex nitidiusculus sp. nov. [referred to as Ca...

Ants exhibit an ancestral trait in which larvae spin silk and cover themselves; however, this trait has been secondarily lost in many subfamilies, genera, and species. The cocoon state should be linked to hygiene strategies for immatures; therefore, it is crucial to understand the diversity of this state. Based on our observations and previous lite...

Simple Summary Similar to wasps and bees, ants also produce their males by parthenogenesis (development from unfertilized eggs). Much more exceptional is thelytoky, which means that female offspring is also produced by parthenogenesis. This phenomenon to date has been reported for only 16 ant species, including three that belong to the genus Strumi...

The ant subfamily Dorylinae consists of the so-called true army ants and their relatives. The latter (= non-army ant doryline genera) was formally known as cerapachyine ants. Among this non-army ant doryline genera, the genus Yunodorylus is part of a clade likely sister related to the Eastern Hemisphere army ants and has remarkable queen morphology...

Our morphological study of the exocrine system in workers of Leptanilla clypeata revealed the presence of at least 23 glands. Among these, the dorsoproximal intramandibular gland represents a novel structure for social insects. Another novel gland may exist in the ventral part of the postpetiolus; both the petiole and postpetiole contain conspicuou...

The Indian jumping ant Harpegnathos saltator is one of the most well-studied ant species; however, little is known about the biology and behavior of sister species in the genus. To understand the universality of the phenomena revealed in H. saltator, biological studies of closely related species are important. We investigated the nest architecture...

Colony composition and behavioral characteristics of the myrmicine ant, Aphaenogaster rugulosa, a species endemic to Yonagunijima Island, were investigated. Colonies nested in rotten woods fallen on the forest floor. All queenright colonies (N＝42) were monogynous with one dealate queen. The average colony size in worker number was 140.5±SD 94.9. Un...

In Japan, nine species have been known in the ant genus Tetramorium , of which five or more are considered tramps. A key to the queens of nine Tetramorium species found in Japan is presented. The tramp species T. tonganum Mayr, 1870 is excluded from the key because no queen was available for us, while T. pacificum Mayr, 1870 is included because it...

The ant subfamily Dorylinae consists of the true army ants and non-army ant genera. The biology of these non-army ants is important in discussing the evolution of the army ant adaptive syndrome. We report on the colony composition, morphological characteristics, and phasic reproduction of a non-army doryline ant Cerapachys sulcinodis species comple...

A colony of Protanilla sp. was collected from the floor of a selectively logged forest in Ulu Gombak, Peninsular Malaysia, in March 2011. The colony contained 17 ergatoid queens and 25 workers. The ergatoid queens had 6–10 ovarioles per individual with a sperm-filled spermatheca while workers had two ovarioles and a vestigial spermatheca. In the la...

The basitarsus of the mid-and/or hindlegs of several Amblyoponinae ants shows a deep longitudinal groove or sulcus on its anterior face in workers and queens. Histological examination reveals this sulcus is associated with a conspicuous novel epithelial gland, which brings the number of exocrine glands in the legs of ants to 25. The ultrastructural...

Thelytokous reproduction by dealate queens in Monomorium hiten Terayama, 1996, collected from four islands of the Nansei Islands (Okinawa Prefecture, Japan) was confirmed in the field and laboratory. Dissection revealed that all dealate queens (N = 38) found in nine field collected colonies were uninseminated. Orphan colonies reared in the laborato...

One colony of Leptanilla clypeata Yamane et Ito was collected in the type locality, the Bogor Botanical Gardens, West Java, Indonesia. The colony was composed of one ergatoid queen, 100 workers, and 120 almost uniformly sized larvae. Queen behavior was observed in the laboratory. As shown in L. japonica by Masuko (1989), the queen showed larval hem...

The ability to express different phenotypes can help define species distributions by allowing access to, and exploitation of, new environments. Social insects employ two markedly different reproductive strategies with contrasting cost/benefit characteristics: independent colony foundation (ICF), which is associated with high dispersal range and hig...

We collected a queenright colony of the very rare Myopias conicara Xu in Vietnam (1 dealate queen, 41 workers and 38 larvae). Both the queen and workers fed on xystodesmid millipedes. After paralyzing a millipede, its head was first removed by the workers, and then the larvae were put on the opening of the collum (anteriormost ring of the trunk). A...

Effects of the invasive Argentine ant, Linepithema humile (Mayr), on a myrmecophilous butterfly, Narathura bazalus (Hewiston), were investigated in the field in western Japan. Larvae of N. bazalus were attended by workers of Argentine ants in invaded parks and of ten native and one cosmopolitan ant species in uninvaded parks. The abundance of eggs...

The ant subfamily Dorylinae contains the true army ant genera, the species of which are dominant predators, as well as non-army ants. Some of the non-army ant genera are closely related to true army ants, so they could be an important key in understanding the evolution of the army ant adaptive syndrome. Nevertheless, there has been little field res...

The present study presents biological observations on colony characteristics of Acanthomyrmex careoscrobis Moffett, 1986 in Ulu Gombak (Selangor, Malaysia), with redescription of the minor worker and descriptions of the hitherto unknown female castes and males. The colony of A. careoscrobis can produce both alate and ergatoid queens. Ergatoid queen...

Recent phylogenetic research indicates that the true army ants (e.g. Aenictus, Dorylus, Eciton, Neivamyrmex) belong to the subfamily Dorylinae, together with several non-army ant genera such as Cerapachys, Yunodorylus, Lioponera and Ooceraea. Thus, comparative studies among doryline genera are very important for understanding the biological charact...

Effects of the Argentine ant on myrmecophilous animals living inside ant nests have been rarely studied to date. We investigated whether the “specialist” myrmecophilous cricket Myrmecophilus kubotai Maruyama that lives only in colonies of a Japanese native ant, Tetramorium tsushimae Emery, could live with the Argentine ant. In the field, the cricke...

Besides the common labial and metapleural glands, four novel exocrine glands are described in the thorax of both workers and queens of the ponerine ant Myopias hollandi. From anterior to posterior, these glands were designated as the propleural pit gland, the posterolateral pronotal gland, the anterolateral propodeal gland and the metasternal proce...

Phenotypic variations are observed in most organisms, but their significance is not always known. The phenotypic variations observed in social insects are exceptions. Genetically based response threshold variances have been identified among workers and are thought to play several important adaptive roles in social life, e.g. allocating tasks among...

In insects, seminal fluid proteins that are produced by male accessory glands and transferred to females during mating have key functions in sperm competition and sperm physiology that lead to male reproductive success. In ants, male reproductive success also depends on the longevity of sperm stored in the queen's spermatheca because their sexual o...

Females of social Hymenoptera only mate at the beginning of their adult lives and produce offspring until their death. In most ant species, queens live for over a decade, indicating that ant queens can store large numbers of spermatozoa throughout their long lives. To reveal the prolonged sperm storage mechanisms, we identified enriched genes in th...

An unusual nesting substrate of a subterranean halictine bee, Lasioglossum (Evylaeus) vulsum (Vachal), was found at Mt Ishizuchi-san, Ehime, Japan. Two nests were obtained from a decaying log in a display sign for a local restaurant. Brood cells, forming a cell cluster, were constructed in a wood hollow with rotted wood fibers pressed together. Nes...

Gesomyrmex (subfamily Formicinae) is a poorly known arboreal ant from the Oriental tropics. We sampled colonies in three localities (NE Thailand, peninsular Malaysia, and Sabah) and examined inhabitants of ten nests inside living branches. None of the nests had a reproductive dealate queen, indicating colonies are polydomous. We distinguished three...

The rove beetle genus Drusilla includes some myrmecophilous species. The Japanese species Drusilla sparsa (Sharp, 1874) has been regarded as a non-myrmecophilous beetle. In Kagawa Prefecture, Shikoku Island, western Japan, however, we often observed that D. sparsa adults were walking in the vicinity of foraging workers of the myrmicine ant Crematog...

Background: Reproductive division of labor is one of the key features of social insects. Queens are adapted for reproduction while workers are adapted for foraging and colony maintenance. In many species, however, workers retain functional ovaries and can lay unfertilized male eggs or trophic eggs. Here we report for the first time on the occurrenc...

7 ชนิ ดเป็ นมดชนิ ดเด่ นที ่ รวบรวมได้ จากแปลงปลู กกาแฟในพื ้นที ่ ภาคเหนื อของ ป ร ะ เ ท ศ ไ ท ย ซึ ่ ง ไ ด้ แ ก่ Anoplolepis gracilipes, Camponotus nicobarensis, Crematogaster sp. PM2, Dolichoderus sp. PM1, Tapinoma sp. PM1, Technomyrmex modiglianii แ ล ะ Technomyrmex yamanei ใน สภาพห้ องปฏิ บั ติ การ ท าการบั นทึ กลั กษณะพฤติ กรรมของมดที ่ มี ต่...

Yunodorylus comprises four named species and lias so far been known exclusively from the Indo-Chinese and Indo-Malayan subregions. Recently, two queen-right colonies of Yunodorylus eguchii Borowiec, 2009 were found in a lowland evergreen forest in Lo Go Xa Mat National Park, southwestern Vietnam. The present paper is the first description of the qu...

The colony structures of social insects vary greatly among species. In ant societies, the number of queens within a colony is variable during colony maturation. We investigated the social structure of a polygynous ant Crematogaster osakensis in a series of field and laboratory experiments. First, the initial colonies headed by multiple queens were...

We collected four solitary queens of the invasive ant Anoplolepis gracilipes under stones in East Java, Indonesia. They produced nanitic workers by claustral colony foundation. This is the first report of independent colony foundation by queens in this species. The discovery may give an important insight into discussion on the origin of this invasi...

Some coffee plantations in Thailand suffer problems caused by the coffee berry borer, Hypothenemus hampei (CBB). Recently, the effects of ants on CBB have been intensively investigated in South America, however it does not investigate in Thailand. As a fi rst step for evaluating ant effects on the CBB in Thailand, the ant species diversity was inve...

The mandibular gland in workers of the formicine ant Myrmoteras iriodum differs from other ants both in its general morphology and ultrastructural organization. The secretory cells appear in a pseudo-epithelial arrangement that gives them a clear polarity. At their apical side, the cells are characterized by a large cup-like extension of the reserv...

Reproductive division of labor is one of the crucial features in social insects, however, the developmental mechanisms leading to modifications in the reproductive apparatus of workers are still not very clear. Ants show a remarkable diversity in the morphological specialization of the worker's reproductive apparatus, that allows to distinguish fou...

I report the colony composition and nesting biology of Platythyrea sp. (parallela-group) in the Bogor Botanic Gardens, West Java. This species, which always nests in trees, reproduces through both dealated queens and mated workers. Among 13 collected colonies, dealated queens reproduced in only one colony, which also contained six mated workers, of...

The defensive function of petiole spines in queens and workers of the formicine ant Polyrhachis lamellidens was investigated using the ant predating tree frog Hyla japonica. Ant workers have hook-like large spines on their petiole while the queen petiole has only small slightly curved spines. Intact workers of P. lamellidens are unpalatable while w...

Polygyny in social insects can greatly reduce within-nest genetic relatedness. In polygynous ant species, potential rival queens in colonies with multiple queens are often executed by other queens, workers, or both. The Argentine ant, Linepithema humile, native to South America, forms a “supercolony” that is composed of a large number of nests and...

Ant colonies are organized similarly to those of wasps and bees: reproductive altruism, age polyethism, and complex communication. Yet ants exhibit more species, much higher total biomass, and their lifestyles and diet are more diverse. Hence, factors additional to sociality must be involved in this evolutionary diversification. We argue that loss...

Our goal was to create colonization and invasion risk maps for the Argentine ant, Linepithema humile, based on occurrence data in Japan, by combining colonization- and invasion-related variables and spatial filters that alleviate spatial autocorrelation. With these data, we will be better able to implement surveillance and control programs. Species...

Ant colonies are organized similarly to those of wasps and bees: reproductive altruism, age polyethism and complex communication. Yet ants exhibit more species, much higher total biomass, and their lifestyles and diet are more diverse. Hence, factors additional to sociality must be involved in this evolutionary diversification. We argue that loss o...

This paper describes the morphological characteristics of nine major exocrine glands in workers of the formicine ant Myrmoteras iriodum. The elongate mandibles reveal along their entire length a conspicuous intramandibular gland, which contains both class-1 and class-3 secretory cells. The secretory cells of the mandibular glands show a peculiar ap...

This study reports on reproduction by ergatoid queens of Monomorium brocha (Bolton) collected in the Bogor Botanic Garden, West Java, Indonesia. One colony fragment comprised 20 ergatoid queens that showed variable ovariole numbers. All but one of the dissected queens had mated, but the ovarian condition varied among individual queens. Ergatoid que...

I studied the myrmicine ant Myrmecina sp. A in West Java, Indonesia, which had the obligately myrmecophilous oribatid mite Aribates javensis in its nests. The oribatid mites cannot survive without ant attendance. The ants rarely eat living mites, but they feed on the mites in case of food shortage and after death of the mites. I examined the effect...

We studied the exocrine system of both workers and ergatoid queens of Protanilla wallacei using light, scanning and transmission electron microscopy. Our survey revealed the presence of 26 glands, of which 6 had never been found before in ants. Five of these represent novel discoveries for social insects in general. The overall novel discoveries co...

The Argentine ant, Linepithema humile, has been spreading via human activities from its native range in South America across much of the globe for more than a century. This invasive ant was first detected in Japan in 1993. Its successful world-wide expansion is attributed to a social structure, namely supercoloniality, whereby individuals from sepa...

Reduction of reproductive organs in workers is one of the most important traits for caste specialization in social insects. In this study, we investigated the morphology of the sperm storage organ, the spermatheca, in workers of the honeybees Apis cerana and Apis mellifera from Japan. All examined workers of the two species retain a small spermathe...

Nest reuse has rarely been observed in Polistes wasps. I observed reuse of an old nest in P chinensis antennalis in Takamatsu, Shikoku Isl. western Japan.

Workers of Crematogaster inflata possess the largest metapleural glands (relative to body size) known among ants, with reservoirs extending anteriorly up to the junction between the pro- and the mesothorax, and with over 1400 secretory cells on both sides together. This large secretory capacity is related to the gland's defensive function, which, i...

ABSTRACT The occurrence,of worker,reproduction,in queenright,and,orphaned conditions,was,studied,in the monogynous,south-east Asian ponerine,ant Odontomachus simillimus. Age (physiological factor), body size and number of ovarioles,(morphological ,factors) and ,antagonistic ,interactions ,among workers,and,egg,cannibalism,(social factors) were,meas...

Gotoh, A., Billen, J., Tsuji, K., Sasaki, T. and Ito, F. 2011. Histological study of the spermatheca in three thelytokous parthenogenetic ant species, Pristomyrmex punctatus, Pyramica membranifera and Monomorium triviale (Hymenoptera: Formicidae). —Acta Zoologica (Stockholm) 00:1–8. The evolution of obligate parthenogenesis may induce the degenerat...

Several ant species show aggression with regard to reproduction among colony members. The frequency of aggression varies with species, season, and/ or colony size. To know the factors affecting this frequency is important for understanding the significance of the aggression. Here we report that in the workerless inquiline ant Vollenhovia nipponica...

Allard, D., Ito, F., Aikawa, Y., Gotoh, A. and Billen, J. 2010. Testes degeneration in ants: a histological study of Gnamptogenys bicolor. —Acta Zoologica (Stockholm) 92: 372–376. Sperm synthesis in the males of social Hymenoptera is not continuous, as the testes degenerate before the males become sexually active. This article presents the first hi...

Thelytokous parthenogenesis in which diploid females are produced from unfertilized eggs, was recently reported for some ant species. Here, we document thelytokous reproduction by queens in the polygynous species Pyramica membranifera. Queens that emerged in the laboratory were kept with or without workers under laboratory conditions. Independent c...

Queen-worker dimorphism, worker polymorphism and worker behavior in the Oriental amblyoponine ant Myopopone castanea were studied. Queen body size was large (head width, 3.0 mm) with 24 to 32 ovarioles while workers showed a remarkable size variation in both body size (head width 1.48 to 2.18 mm) and ovariole number (6 to 22). Both head width and a...

Colony composition and morphological caste differentiation between queens and workers were studied in 14 Leptogenys species collected in Malaysia and Indonesia. Ten species had ergatoid queens and four species reproduced by mated workers without morphologically distinct queens. Colonies of most species having ergatoid queens were monogynous, howeve...

The colony composition of the ponerine ant Pachycondyla (=Bothroponera) tesseronoda was studied in Mudigere, southern India. The colonies (n = 9) each consisted of 102 (± SD 28) workers on average, without morphologically distinctive queens. Instead, one to eight gamergates (inseminated and egg-laying workers) per colony reproduced. Virgin workers...

Foraging strategy of ant workers has been studied from several aspects, however, the mode of prey retrieval and factors affecting it have been rarely studied to date, even thought it is an important aspect for understanding ant foraging strategy. We investigated the behavioral response against large prey for 44 ant species of 34 genera belonging to...

Division of labour improves fitness in animal societies. In ants, queens reproduce, whereas workers perform all other tasks. However, during independent colony founding, queens live as solitary insects and must be totipotent, especially in species where they need to forage. In many ants, solitary founding has been replaced by dependent founding, wh...

In many ant species, the queens can keep spermatozoa alive in their spermatheca for several years, which goes along with unique morphological characteristics of the queen's spermatheca. The relative spermatheca size in ant queens is prominently larger than that in social wasps. Furthermore, the epithelium lining the spermatheca reservoir of ants co...

Prey composition of the Japanese treefrog, Hyla japonica GUÄNTHER, 1859, was investigated in an area invaded by thebb Argentine ant, Linepithema humile (MAYR, 1868). Ants were the most common taxa among the prey animals in your treefrogs, constituting 82.4% of the numeric proportion and 49.9% of the volumetric proportion of all prey items in the fr...

Ant effects on the community of weevils were studied in a Quercus dentata chaparral of Ishikari Coast, northern Japan, where a supercolony of the red wood ant Formica yessensis expands over the dune. A total of 16 species of weevils were collected in the present survey. The dominant species were Myllocerus griseus, Phyllobius longicornis, Rhynchaen...

Colony composition and behavior of ergatoid queens were investigated in two species of the Leptogenys diminuta group (L. diminuta Smith F. and L. sp. 12) in Indonesia. Average number of workers in queenright colonies was 277 ± 116 and 422 ± 176 in L. diminuta and Leptogenys sp.12, respectively. Most colonies had one physogastric mated ergatoid quee...

We describe colony composition and reproductive and behavioural characteristics of Gnamptogenys cribrata. Colonies are monogynous, composed of one dealate queen and an average of 27 workers. This species shows the unusually low number of two ovarioles (1 - 1) in both queens and workers. The queen shows larval hemolymph feeding. Workers laid two dis...

Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term storage of sperm. Such 'non-sexual' workers are restricted to laying unfertilized eggs that give rise to males, and they cannot compete with the queens for the production of female offspring. In sharp contrast, workers in...

Social wasps show an obvious evolution of the differentiation in behavior and external size between reproductive and non-reproductive females, with no clear differences in the Stenogastrinae, via overlap in the Polistinae, to clear differences in the Vespinae. In this study, we examined the morphological appearance of the spermatheca in representat...

The effect of an Argentine ant invasion on the abundance of the myrmecophagic jumping spider Siler cupreus Simon was investigated in the Hiroshima Prefecture, southwestern Japan. The frequency and density of S. cupreus were significantly higher in sites infested with Argentine ants than in ant-free sites. S. cupreus actually preyed on the adult ant...

The chemistry of the exocrine glands of three species of the small and little-known ant subfamily Cerapachyinae has been examined for the first time. The mandibular glands of Cerapachys jacobsoni contained acetophenone and skatole, but some individuals contained, in addition, 4-methyl-3-heptanone and 3-octanol. The mandibular glands of the new spec...

Investigation of reproductive strategies of ants in the subfamily Ponerinae is important for understanding of the evolution of social structure and of the significance of caste dimorphisms. The biology of species with mated and egg-laying workers (gamergates) has been studied for many species, however, little attention has been paid to species that...

The distribution of the Argentine ant, Linepithema humile, was investigated in 65 cities or towns along the Seto Inland Sea, western Japan in 2003–2005. Our results include all available information of their distribution in Japan until 2005. Argentine ants have invaded Aichi Prefecture (Tahara-shi), Hyogo Prefecture (Kobe-shi), Hiroshima Prefecture...

香川県丸亀市飯野山のアリ相を報告した。 合計33種が記録された。いずれの種も，これ まで既に香川県から記録がある種であった。

Ant queens mate when young and store sperm in their spermatheca to fertilize eggs for several years until their death. In contrast, workers in most species never mate. We have compared the histological organization of spermathecae in 25 poneromorph species exhibiting various degrees of queen-worker dimorphism. The spermathecae of both castes in all...

The tegumental epithelium of the outer dorsolateral region in the proximal part of the coxae in the mid- and hindlegs of both workers and queens of the ants Odontomachus rixosus and O. simillimus is differentiated into a conspicuous and hitherto unknown exocrine gland. The glandular cells display a clear microvillar differentiation of their apical...

Some myrmecophilous animals show myrmecomorphy, however, its adaptive significance is still controversial. We investigated a possible benefit of Batesianmimicry between a myrmecophilous staphylinid beetle, Pella comes, and its host ant, Lasius (Dendrolasius) spathepus, by using a common ant predator, the Japanese treefrog, Hyla japonica. In the fie...

In queenless ants, gamergates (mated egg-laying workers) fulfil the reproductive task normally reserved for the queen. Every worker is a potential gamergate, thus we expect pronounced conflicts over sexual reproduction within their colonies. In the queenless ant genus Diacamma, gamergates inhibit nest mates from mating by aggressively removing (‘mu...

Workers of the ant Amblyopone reclinata employ solitary prey retrieval when prey is small, but recruit nestmates to large prey. In the latter case, the scout forager paralyses the prey with its powerful sting, and quickly returns to the nest. During this homeward journey, it deposits a trail pheromone, that originates from the well developed footpr...

Queen behaviour of Leptothorax acervorum collected in northern Japan was observed in four func- tionally monogynous colonies (one functional mated egg-laying queen with some supernumerary mated but sterile queens) and two monogynous colonies with some virgin queens. In three functionally monogynous colonies, domi- nance behaviour including antennat...