Inter- and intraspecific alarm response in the termiteMacrotermes subhyalinus (Rambur)

Summary In laboratory studies we analysed the reaction of aMacrotermes subhyalinus (Rambur) colony in contact with a small group of test termites placed at the head of a gallery system. As test termites we usedMacrotermes subhyalinus of the same nest,Macrotermes subhyalinus of a foreign nest and the related sympatric speciesMacrotermes bellicosus (Smeathman).Contact with an introduced group of foragers evokes a significant recruitment of workers and minor soldiers. The intensity of the response depends on the test groups we introduced. The highest recruitment results withM. bellicosus andM. subhyalinus from a foreign nest. During the recruitment the increase in the number of minor soldiers is greater than the increase in the number of workers, and as a result, the relative proportion of the soldiers in the population leaving the nest is significantly higher than before.Direct observations at the place of contact show thatM. bellicosus individuals are immediately attacked and killed. In the case ofM. subhyalinus from a foreign nest, not all individuals are killed; some are only intensively examined with the antennae or seized with the mandibles.M. subhyalinus from the same nest are rarely attacked. Mostly they are antennally inspected or enter the gallery system unhindered.The recruitment of termites from the nest is released by major workers which, after contact with the test termites, run back into the nest and provoke an alarm by tactile stimuli. On their way back into the nest the major workers, in all probability, lay a pheromone trail which leads the outgoing alarmed termites towards the place of contact.     

Diel changes of temperature in the nests of two Polybia species, P. paulista and P. occidentalis (Hymenoptera, Vespidae) in the subtropical climate

Temperatures in two mature Polybia nests were measured to study the thermal conditions of nests. Temperatures in a Polybia paulista nest were measured when it had adult wasps (trial 1) and after the adult wasps were removed (trial 2), and temperatures in a P. occidentalis nest were measured when inhabited by adult wasps (trial 3). In each trial, C–C thermocouples were set at four points in the nest and at two points outside to discover the ambient and substratum temperatures. In trial 1, nest temperatures basically followed the ambient temperature, but during the day the nest temperatures were lower than the ambient temperature and this relationship was reversed during the night. The temperature fluctuation of the inner substratum points was smaller than that of the outer points. The trend of trial 2 was closely similar to that of trial 1, showing a virtual lack of thermal effects from the presence of adult wasps. In trial 3, the changing pattern in the P. occidentalis nest showed a trend similar to that in the P. paulista nest, but the inside temperatures rose quickly when the nest received direct sunlight in the morning. From these results, thermal characteristics in the Polybia nests are discussed in relation to the nest architecture and their geographical distribution.     

Nest-plugging: interference competition in desert ants (Novomessor cockerelli and Pogonomyrmex barbatus)

Summary Pogonomyrmex barbatus and Novomessor cockerelli, sympatric species of harvester ants in the Lower Sonoran desert, compete for seed resources. This study reports on a method of interference competition. Early in the morning, before P. barbatus' activity period, N. cockerelli fills the nest entrances of P. barbatus with sand. This delays the beginning of the P. barbatus activity period for 1–3 h. P. barbatus colonies near N. cockerelli nests were more likely to be plugged. Nest-plugging shifts the typical daily sequence of P. barbatus activities, including the onset of foraging, forward towards midday, when high temperatures force the colony back inside the nest. P. barbatus colonies do not compensate for late emergence or events impeding foraging by increasing foraging rate. Thus nest-plugging by N. cockerelli decreases the foraging capacity of P. barbatus colonies.     

Site selection by a social wasp in a nesting association (Hymenoptera: Vespidae)

The tropical social waspMischocyttarus immarginatus is a nesting associate ofPolybia occidentalis in northwestern Costa Rica. We show that an activeP. occidentalis colony is a necessary component of aM. immarginatus nesting site in this part of the latter’s range.M. immarginatus foundresses actively seekP. occidentalis colonies to initiate nests at a modal distance of 8 cm from them. There is an 18-mm lower limit to how closeM. immarginatus can nest in relation toP. occidentalis. At distances of less than this,P. occidentalis workers can reach theM. immarginatus nest while standing on their own nest and robM. immarginatus of its brood when the adults are absent.     

Parasite presence acts as a proximate cue in the nest-site selection process of the solitary digger wasp,Ammophila dysmica (Hymenoptera: Sphecidae)

Nest-site selection by the solitary ground-nesting wasp Ammophila dysmicaMenke was studied during 1982–1986 in California's Sierra Nevada Mountains. Digging females detected and discriminated among members of a complex of insect intruders, including a number of predators and parasites. In response to some natural enemies, wasps sometimes permanently abandoned nests under construction. These selective nest abandonments reduced the mean number of cleptoparasitic chrysidid wasps, Argochrysis armillaBohart, attending the excavation of completed nests. The number of A. armillaattending a nest excavation correlated positively with the probability of nest parasitism by this species. Selective nest abandonment may reduce parasitism rates.     

Predation by the grey leaf monkey (Presbytis hosei) on the contents of a Bird's nest at Mt. Kinabalu Park,Sabah

An adult male grey leaf monkey (Presbytis hosei) was observed in Mt. Kinabalu Park, Sabah, Malaysia, raiding the nest of a grey-throated babbler (Stachyris nigriceps). The monkey removed from the nest and ate at least two eggs and perhaps one young hatchling. This incident appears to be the first reported case of anyPresbytis spp. consuming animal prey.     

Patterns in foraging and nesting ecology in the neotropical ant, <Emphasis Type="Italic">Gnamptogenys moelleri</Emphasis> (Formicidae,Ponerinae)

Summary This study provides quantitative field data on the natural history and foraging behaviour of the Neotropical bromeliad-nesting ant Gnamptogenys moelleri (Ponerinae) in a sandy plain forest in Southeast Brazil. The ant nested on different bromeliad species and the nests were more frequently found in bigger bromeliads. The species used a wide array of invertebrates in its diet, hunting for live prey and scavenging the majority of the items from dead animals. The food items varied greatly in size (1 to 26 mm). Hunting was always performed by solitary workers. Retrieving was performed by solitary workers (small items), or by a group of 3 to 12 workers recruited to the food source (large items). Almost all G. moelleri foraging activity was restricted to the nest bromeliad. In the warm period more ants left the nest to forage, and foraging trips achieved greater distances compared to the cool season. Trap data revealed that overall availability of arthropod prey is higher in the summer than in the winter. The opportunism in nest site use and in foraging behaviour, the small foraging area, as well as the seasonal differences in foraging activity are discussed and compared with other tropical ants.Received 30 May 2003; revised 22 September 2003; accepted 3 October 2003.     

Aspects of breeding ecology of the eastern olivaceous warbler (Hippolais pallida)

The breeding ecology of eastern olivaceous warblers Hippolais pallida is poorly known. In this study, we provide data on nest site selection and breeding parameters of the species in a population in northwestern Bulgaria, the only one known to be regularly and heavily parasitized by the common cuckoo Cuculus canorus (hereafter cuckoo). Eastern olivaceous warblers only bred within human settlements of the study area, avoiding seemingly suitable habitat outside them. Nests were built in a wide range of plant taxa but ailanthuses Ailanthus altissima and mulberries Morus spp. were most frequently used (21%). After taking into account the availability of vegetation, there was an apparent preference for several plant taxa but not for mulberries. Mean nest height was 1.65 ± 0.98 (0.53–7.60) m, n = 217, and it varied significantly among different types of nesting substrate. Laying date and clutch size of first breeding attempts averaged 10 June ± 0.98 days, n = 101 and 3.9 ± 0.07 (2–5) eggs, n = 72, respectively. Hatching success, fledging success, and breeding success were 42.5, 86.4, and 36.7%, respectively. The main sources of nest mortality were predation and cuckoo parasitism, with no significant difference in the proportion of nests lost to each. Cuckoo parasitism seemed responsible for the relatively low hatching success in this population.     

Reproductive seasonality and nest-site differentiation in three closely related armoured catfishes (Siluriformes: Callichthyidae)

Synopsis Three sympatric, closely related armoured catfishes showed a similar, bimodal breeding season in coastal plain swamps in Suriname (South America). The bimodal pattern of reproduction inCallichthys callichthys,Hoplosternum littorale andHoplosternum thoracatum was correlated to the annual distribution of rainfall. Floating bubble nests were constructed throughout the period of swamp inundation (rainy season). Close inspection of the timing of reproduction ofH. littorale in northern South America revealed the relationship between reproduction and rainfall, but also unexpected differences in the length of the breeding season. Strong interspecific competition among the three species was probably avoided through differentiation of nest sites with respect to water depth, distance to the nearest tree, distance to the edge of the swamp, and cover above the nest. Nests ofH. littorale were built in herbaceous swamps, whileC. callichthys andH. thoracatum build their nests in swamp-forest. Nests ofC. callichthys were observed in extremely shallow water or in holes. Few nests of the three species were observed in canals. Over large parts of their geographical rangeC. callichthys andH. thoracatum are found in small rainforest streams. Several aspects of the reproductive ecology and behaviour of both species are probably related to the unpredictability of the stream habitat.     

Nesting biology and nest re-use ofEulaema nigrita (Hymenoptera: Apidae,Euglossini)

Summary The nesting behavior of the euglossine beeEulaema nigrita was observed in the laboratory after being transferred from three nests to observation boxes. Nests were re-used by successive generations with more than one female working in each re-use process. Associated females were always of the same generation. All females that shared a nest foraged for construction materials (mud, excrement and resin) and each constructed, provisioned and oviposited in her own cells. The number of cells constructed by each female ranged from one to 23. Females stayed in the nests for periods ranging from 15 to 59 days during the hot and wet season and from five to 78 days during the cool and dry season. The egg-to-adult period was related to climatic conditions, and in all re-use processes it was longer than the time of residence of the females in the nests. The meloid beetleMeloetyphlus attacephalus was the only nest parasite. Due to the attack method employed by this parasite, the presence of more than one female in the nest did not result in improved nest defense.     

Observation of group recruitment to prey in a primitive ponerine ant,Amblyopone sp. (reclinata group) (Hymenoptera: Formicidae)

Summary Group recruitment during foraging was observed in a primitive ponerine ant,Amblyopone sp. (reclinata group) under laboratory condition. Workers searched for prey singly; however, if a item of prey was stung by a worker, other ants joined the attack. After the prey became immobile, one of the workers laid a trail directly toward the nest. This scout worker recruited additional workers (between 3 and 33). They formed a single file procession to the point of prey capture, and cooperatively transported the prey. A scout worker could stimulate nest workers to leave the nest without direct contact, and the recruited workers could trace the trail without guidance by the scout worker. This is the first report of recruitment behavior during foraging in the primitive antAmblyopone.     

Landmark orientation during the approach to the nest in the stingless beeTrigona (Tetragonisca) angustula (Apidae,Meliponinae)

Summary We displaced a small nest box containing stingless bees (Trigona (Tetragonisca)angustula) over distances of up to 1.6 meters in different directions and counted the numbers of returning foragers to measure the effects of this manipulation on the homing ability of bees. Bees find it hard to locate the nest box when it was displaced more than about 1 m backwards, forwards or sideways relative to the direction into which the nest entrance pointed. They do not find the nest when its height above ground is changed. The bees use landmarks in the vicinity of the nest to locate it: When the nest box is displaced and landmark positions are changed so that their angular position at the new nest site is the same as at the normal nest position their homing ability is less impaired than it is without changes in landmark positions. Our results show that the bees do not use the nest box itself as a landmark until they have approached the nest position to within about 1 meter with the aid of surrounding landmarks.     

Temporal relationships of rubbing behavior with foraging and petiole enlargement inParapolybia indica (Hymenoptera: Vespidae)

Summary The frequency of application of ant repellent secreted from the metasomal sternum VI gland to the nest petiole (=rubbing behavior) inParapolybia indica colonies decreased significantly from the preemergence, single-foundress stage to the post-emergence stage. In the pre-emergence stage, rubbing occurred in close temporal association with the departure from the nest, which may maximize the antrepelling effect of the rubbing substance during the period when the nest is not attended by any wasps. On the other hand, only a small proportion of the departures was associated with rubbing in the post-emergence stage.Unlike in other independent-founding polistine wasps, rubbing inP. indica was not associated with petiole enlargement. Among independent-founding polistines,P. indica is unusual in that females enlarge the nest petiole with a large amount of plant fibers instead of strict use of adult saliva, and in that the petiole surface is rough, and may be much more absorbent than that of the secretion petiole. On the other hand, in the species showing a temporal association between petiole enlargement and rubbing, females typically rub immediately after petiole licking (application of oral secretion). This fact, and the lack of such a temporal association inP. indica, may suggest a possibility that the mixture of oral secretion and rubbing substance on the smooth surface of the secretion petiole makes the chemical barrier last longer.     

Individual scent marking of the nest entrance as a mechanism for nest recognition inXylocopa pubescens (Hymenoptera: Anthophoridae)

The mechanism by which female Xylocopa pubescenslocate their nest in a nesting aggregation was investigated. The bees were induced to nest in canes to which uniform nest entrances were attached. The results of nest displacement experiments revealed that the bees use visual cues for proximate orientation,but at very close range they also use olfactory cues. This conclusion was corroborated by the results of experiments in which the nest entrances were either removed or exchanged for alien nest entrances. Moreover, habituation experiments strongly indicated that the bees impart their individual marking at the nest entrance and that they can learn and memorize the individual odors of the neighboring bees.     

Usurpations and late associations in the solitary founding social wasp,Polistes biglumis bimaculatus (Hymenoptera: Vespidae)

One hundred twenty-five colonies of a population of the montane, haplometrotic, paper waspPolistes biglumis bimaculatus were marked for identification and then periodically surveyed during an entire summer period. This made it possible to record intraspecific nest usurpations (both single and multiple) and to observe associations between two females, defined here as late associations. Both usurpation and late association occurred primarily in the latter half of the preemergence period. Some evidence suggests that a foundress usurps a conspecific nest as a consequence of her own nest failure. After nest failure, usurpation and late association are the only available options for achieving reproductive success because, in the mountain habitat, the short summer does not allow for successful renesting. Late associations generally occurred earlier than usurpation. However, our evidence suggests that nest usurpation and late association may be the same phenomenon.     

Food and reproductive strategies of the myrmecophilous staphylinid beetleHomoeusa acuminata (aleocharinae) on the foraging trails of its host antLasius fuliginosus (Hymenoptera: Formicidae)

Summary The trail following behaviour of the adult myrmecophilous beetleHomoeusa acuminata on the foraging trails on the host antLasius fuliginosus was examined in June and all the observed behaviours were quantified. The beetle appears as a food robber, using the stowaway behaviour which consists of attaching itself to prey transported by ants to the nest. Foraging trails are also used by the beetles as a meeting place for mating. However, the beetle does not enter into the nest and appears as a symbiont poorly integrated in the social life of its host.     

Intraspecific nest parasitism in the grey starling (Sturnus cineraceus)

We studied intraspecific nest parasitism in the grey starling (Sturnus cineraceus) in 1992 and 1993. We used three criteria to detect nest parasitism: (i) the appearance of more than one egg per day while the host was laying; (ii) the appearance of extra eggs after the host completed its clutch; and (iii) the appearance of eggs which were of a different shape, size and color to other eggs in the clutch. There were 290 nests (157 nests in 1992; 133 nests in 1993) in which the clutch was completed early (clutches initiated before May 10). Twenty-nine (1992) and 32 (1993) nests contained at least one parasitic egg. Parasitic eggs hatched if they were laid during the laying period and early in the incubation period of their host, and a few of them fledged. Fledging success of parasitic eggs was not different from that of eggs in non-parasitized nests if parasitic eggs were laid during the host's laying period. However, fledging success of all parasitic eggs was fewer than that of eggs in non-parasitized nests. By comparison, fledging success of parasitized nests was not a great as that of non-parasitized nests.     

Behaviour in usurpers and late joiners ofPolistes biglumis bimaculatus (Hymenoptera,Vespidae)

Summary During the late pre-emergence phase, a foundress of the paper waspPolistes biglumis bimaculatus may be expelled by a conspecific female from her own nest (usurpation) or, less frequently, joined by another female of the same species (late association). The behaviour of femalePolistes biglumis bimaculatus, when usurping a conspecific colony or joining another foundress, is compared with that of foundresses on non-usurped colonies. The most conspicous difference is the intense abdomen stroking behaviour the usurper performs over the comb surface on the first days after usurpation. As observed in otherPolistes species, once usurpers and joiners arrive on a strange nest they will destroy most of the immature brood of the previous nest owner. Although host workers are not aggressive towards the intruder females, reproductive success of usurpers and joiners is low compared with that of legitimate foundresses. The same behaviours observed on usurped colonies are found in the obligate social parasites ofPolistes. These behaviours are therefore discussed in the context of the evolution of intra- and inter-specific parasitism.     

Ant nests as primary habitats ofSilybum marianum (Compositae)

The common Mediterranean ruderal thistleSilybum marianum is associated with nutrient-rich sites. Its wind-dispersed achenes possess an oily food body, that is attractive to harvester-ants. Following removal of the oily body, the achenes are deposited in the refuse zone together with rich organic material and soil removed from the nest; while in the nest the achenes are partly protected from fires. The thistle grows successfully in the nutrient-enriched refuse zone and thus dominates patches in the grassland. Preadaptations to live in association with harvester-ants enableS. marianum to occur also on marking stations of male gazelle, on cattle dung deposits, and in synanthropic ruderal habitats.     

Biology of <Emphasis Type="Italic">Lasioglossum</Emphasis> (<Emphasis Type="Italic">L.</Emphasis>) <Emphasis Type="Italic">majus</Emphasis> (Hymenoptera: Halictidae), a largely solitary sweat bee with behavioural adaptations to communality

Within the bee family Halictidae there have been three origins of sociality. Although detection of origins and reversal from sociality requires phylogenetic studies, at a behavioural level a predisposition to sociality can be detected by analysis of intra-specific interactions. We studied aspects of nesting biology and behavioural interactions in Lasioglossum (Lasioglossum) majus, a poorly known halictine inhabiting temperate regions of Europe, which is suspected to be solitary. Nests were found to be largely used by one female, but some were shared by more than one individual. These few nests, whose entrances were very close to each other, were found to be connected underground. A few individuals were observed to enter in a nest where a female was waiting, behaving as a guard and allowing the incoming bee to enter the nest. By use of circle-tube experiments, the behavioural repertoire exhibited by females during encounters was assessed. Levels of withdrawal and cooperative events were comparable with those observed in other solitary nesting species, but aggressive events were very rare, as in several observed communal species. We conclude that L. (L.) majus females, despite general solitary nesting, possess behavioural components enabling them to adopt, probably in high nest-density areas, nest-sharing strategies. A similar kind of local social polymorphism has been observed in two other species of the subgenus Lasioglossum, but these are the first data available on a European species and the first record of subterranean connections among nests of halictid bees.