Predator-prey interactions between the digger wasp Clypeadon laticinctus and the harvester ant Pogonomyrmex occidentalis

Females of the digger wasp Clypeadon laticinctus prey exclusively on workers of the western harvester ant Pogonomyrmex occidentalis. There is considerable variability in the size of ant workers both within and between ant mounds, and wasps tend to select larger workers as prey. Worker ants were most likely to be outside the nest at surface temperatures of 25–35°C. Wasps were seen at ant mounds most frequently when surface temperatures were between 40 and 50°C. Wasps captured ants outside and inside ant nests. Predation attempts were equally likely to result in a successful capture in either location, but entering the ant nests was more time consuming. Approximately 63% of visits by wasps to ant mounds resulted in a successful prey capture. In general, ant mounds that were visually conspicuous or close to wasp nest aggregations were more likely to be visited by wasps. However, frequency of visitation and rates of predation at a given mound varied considerably from week to week. Agonistic interactions between female wasps involving chases and occasional fights were likely to occur whenever two wasps were simultaneously present at an ant mound, especially when the only access to prey was by entering the mound.     

Predatory habits of the grasshopper-hunting wasp Stizus continuus (Hymenoptera: Crabronidae): diet preference,predator–prey size relationships and foraging capacity

In a coastal salt-marsh of Spain, the digger wasp Stizus continuus primarily hunted for grasshoppers of the genus Heteracris, revealing (at least in the period of the study and in this area) this wasp to be almost monophagous. In contrast, grasshoppers of the genus Acrotylus were ignored by the wasps in spite of their high abundance in the environment. We hypothesize that this bias occurred because Acrotylus is found more often on the soil and on grasses, while Heteracris is nearly only found on Sarcocornia bushes, which probably represent the habitat mostly exploited by the wasps for hunting. The greater variance in size of the prey collected by larger females produced weak wasp–prey size correlations. Some wasps were observed to carry in flight prey weighing close to or more than the maximum theoretically possible, suggesting that they have to descend with prey to the nest from the above-soil hunting sites.     

An overview of the mite fauna (Acari) associated with eumenine wasps (Hymenoptera: Vespidae) found in Brazilian collections

ABSTRACT

Mites can be associated with other organisms as parasites, commensals, phoretic, among others, such as some Winterschmidtiidae that present cooperative relationships with solitary wasps (Eumeninae). These wasps have one or more cavities in their body surface that are capable of carrying mites, called acarinaria. Studies carried out in the northern hemisphere suggest that these relationships are species-specific. However, in South America, there are few studies in this field. Aiming to recognize and increase our knowledge of the species of solitary wasps from Brazil that are associated with mites, we examined 61 wasps belonging to 29 species and four genera from Brazilian museum collections. All of the specimens studied presented at least one type of acarinarium in their bodies. There were mites in all specimens of wasps, but not all of them were associated with an acarinarium. The mites belong to 11 different genera: six in Winterschmidtiidae (possibly cooperation relationships); one in Oplitidae (phoresy); one in Erythraeidae (parasitism); two in Acaridae (phoresy); and one in Histiostomatidae (phoresy). Detrended correspondence analysis and indicator species analysis were conducted to test the preference of the mite genera for species of wasp and for site (regions of the wasp’s body). These tests were significant only for the mite genus Vespacarus preferring Parancistrocerus wasp species and the metasomal acarinaria. Some of the mites did not have a specific host, and some wasps carried more than one species of mite, differing from the specific interactions reported for the northern hemisphere.     

First record of a non-pollinating fig wasp (Hymenoptera: Sycophaginae) from Dominican amber,with estimation of the size of its host figs

Fig trees and their pollinating fig wasps arose about 75 million years ago in the Cretaceous period. Several other groups of chalcid wasps also utilize figs for larval development, including sycophagines, the putative sister group to pollinating fig wasps. Whereas stone and amber fossil pollinators are known, no fossils representing non-pollinating fig wasp groups have been confirmed previously. Here, we describe the first Sycophaginae from the c.15–20 Ma Dominican amber, Idarnes thanatos sp. nov. Farache, Rasplus, Pereira and Compton, and discuss its relationships within the Idarnes carme species group. Additionally, we use linear regression to compare body size, ovipositor sheaths length, and host fig size data from extant Idarnes species to estimate the size of its host figs. Idarnes thanatos was most likely associated with small to medium sized figs (diameter ≤1.0 cm), that were likely to have been dispersed by birds and primates. The discovery of this close relative of extant non-pollinating fig wasps suggests that early Miocene and modern fig wasp communities may share similar ecological and functional features.     

The natural history of the parasitic wasp Trogus pennator (Hymenoptera: Ichneumonidae): Host‐finding behaviour and a possible host countermeasure

The parasitic wasp Trogus pennator (Ichneumonidae) attacks the larvae of swallowtail butterflies (Papilionidae). Female T. pennator were followed in the field as they searched for larvae of the zebra swallowtail butterfly, Eurytides marcellus (Papilionidae), feeding on Asimina (Annonaceae) in central Florida, USA. Predictions of host‐finding theory and interactions with the host were thus investigated in a natural setting. Wasps seldom flew to plants other than Asimina and apparently recognized the plants by visual cues. Plants were attractive regardless of host presence, as the wasps approached plants lacking E. marcellus feeding damage twice as often as they approached damaged plants. However, wasps approached damaged plants at a rate greater than their frequency in the Asimina population, indicating that they can detect host damage before they approach the plants. After approaching within 0.5?m of plants, wasps tended not to land on plants lacking feeding damage. A comparison of the plants they landed on, however, showed no consistent preferences for damaged plants. The weaker trends in the latter data indicate that the presence of feeding damage was not the sole criterion for landing, although it evidently influenced behaviour. After landing, wasps spent more time searching damaged plants than undamaged plants. Butterflies preferred to oviposit on plants shorter than those searched by T. pennator. Possible adaptive consequences of this phenomenon are discussed.     

Notes on the natural history of Stizus perrisii ibericus Beaumont (Hymenoptera: Sphecidae)

A study of the biology of Stizus perrisii ibericus revealed some aspects about the behaviour of males, the nesting behaviour of females, and larval development. The slow mass provisioning of this species is compared with the provisioning behaviour of S. continuus and S. pulcherrimus. Cocoons are constructed in seven stages although, compared with other species, there are differences in the duration of each stage. Natural enemies of the wasp include miltogrammine flies, several cuckoo wasps, and velvet ants.     

Life cycle and behaviour of Charoxus spinifer and Charoxus major (Coleoptera: Staphylinidae: Aleocharinae), predators of fig wasps (Hymenoptera: Agaonidae)

Charoxus spinifer is associated in southern Florida with native fig trees (Ficus aurea and Ficus citrifolia). Winged adult beetles, 3.0–3.6 mm long, mate on Ficus twigs outside the syconia (fruits), and enter the syconia through holes cut by male pollinating wasps. Adults and larvae eat adult wasps within the syconia. Ovaries hold few, large, mature eggs. Larvae develop through three instars. Fully grown larvae abandon the syconia, drop to the ground, burrow to a depth of 1.5–3.7 cm, spin a silken cocoon, and pupate. Pupal duration is 8–9 days. Larval populations are highest in May, when penultimate stage syconia (phase D) are most abundant, but were detected in all months except June. Charoxus major is reported from Veracruz, associated with Ficus lapathifolia. Its adults extract wasp occupants of galled fig ovaries within syconia, and its eggs were found singly in empty galls.     

Life cycle of Huarpea fallax (Hymenoptera: Sapygidae) in a xeric forest in Argentina

This study describes the life cycle of Huarpea fallax (Hymenoptera: Sapygidae) in a xeric forest in La Pampa province, Argentina. This cleptoparasitic wasp attacks the nests of two species of leaf-cutter bees: Megachile catamarcensis and Anthidium vigintipunctatum, both belonging to the family Megachilidae. Nests of these bee species were obtained during a trap-nesting programme. Adult emergence showed a unimodal pattern indicating a univoltine life cycle. The period from egg-laying to adult emergence lasted for 10–13 months; however, one female took about 2 years to emerge, suggesting parsivoltinism. Most females attack one cell per host nest, the outermost cells being the ones most parasitized. However, the position of the attacked cells was variable. In this paper, although there were insufficient data to prove a correlation, the data suggest a positive trend between body size of sapygid wasps and their host bees.     

Antennation and sexual performance of male digger wasps Sphex ingens Smith (Hymenoptera: Sphecidae)

Antennation can play several roles in hymenopteran copulation, mainly in wasps. The digger wasp Sphex ingens Smith has a very peculiar sexual behaviour, in which forced copulation is a striking element. However, communication through antennation during the pre-copulation and copulation phases and the relationship between the sexual performance of males and the final result of copulation require further clarification. The sexual behaviour of wild populations of S. ingens was filmed during the breeding season in a site between the beaches Meros and Aventureiro, Ilha Grande, southeastern Brazil. We assessed antennation behaviour, courtship duration, sexual performance, and genital clasping. Only successful males had the genital clasping assessed. Evidence found so far points out that the successful males showed better sexual performance – that is, they antennated more in a shorter courtship duration. Also, genital clasping in successful males did not depend on antennation, courtship duration, or sexual performance. Our results shed light on some aspects of the sexual behaviour of wasps, as they explain part of the sexual selection mechanisms adopted by the species.     

Time-lapse photography reveals the occurrence of unexpected bee-pollination in Calanthe izuinsularis,an endangered orchid endemic to the Izu archipelago

Calanthe izuinsularis is a rare, beautiful and fragrant orchid endemic to the Izu archipelago. Although it is known that mainland populations of closely related Calanthe species are pollinated by medium- to large-sized bees, it is likely that C. izuinsularis has been forced to alter its floral biology to attract alternative pollinators, as large-sized bees are rarely found on the Izu Islands. Indeed, the unusual floral characteristics of C. izuinsularis, which produces pale flowers that emit a strong and fragrant scent during the night, are considered the adaptation to a moth-pollinator syndrome. As expected, our time-lapse photography using a digital camera revealed that the inflorescences of C. izuinsularis were most frequently visited by nocturnal moths such as Noctuidae, Geometridae and Crambidae, which accounted for 50% of all insect visits (in terms of both the number of frames with captured visitors and the number of times visited). However, our study could not provide evidence of a pollinator shift towards moths because none of the moth species was observed with pollinaria. On the other hand, our study found that the pollinaria of C. izuinsularis could become attached to the mesothorax of the small-sized sweat bee Lasioglossum occidens. Therefore, our study suggests that C. izuinsularis is still somewhat dependent on bee pollination, while the orchid has changed its floral colouration and scent. The occurrence of bee-pollination in C. izuinsularis would provide an explanation for how the natural hybridisation between C. aristulifera, C. discolor and C. izuinsularis can occur.     

The scramble competition mating system of the sphecid wasp Palmodes praestans (Kohl)

Males of the wasp Palmodes praestans engage in non‐territorial patrolling behaviour within a scramble competition mating system, showing great fidelity to their wide‐ranging patrolling routes without attempting to monopolize the areas covered. Scramble competition appears adaptive given that mating opportunities are not spatially aggregated in this species, whose females build isolated, single‐celled nests. Because of the female distribution pattern, a male's reproductive success in P. praestans probably depends upon the ability to find highly scattered, unmated females. The females of some close relatives of this sphecid wasp form fairly dense nesting aggregations. As mating system theory predicts, the males of some (but not all) of these species focus their searching at these concentrated nesting/emergence sites where potential mates are clustered spatially.     

Host–parasite relationships and life cycles of cuckoo wasps in agro-ecosystems in Argentina (Hymenoptera: Chrysididae: Chrysidini)

Chrysididae is a diverse group of parasitoid/cleptoparasitic wasps; however, host–parasite relationships and life cycles of few species have been studied. Nests of different wasp and bee species were obtained during a trap-nesting programme, in the Pampean region. Some of these nests were parasitised by cuckoo wasps females of Caenochrysis taschenbergi (Mocsáry), Chrysis boutheryi (Brèthes), C. saltana Bohart, C. sp. 1 (ignita-group), C. sp. 2 (ignita-group), Neochrysis lecointei (Ducke), Pleurochrysis ancilla (Buysson) and P. lynchi (Bréthes). This paper reports new data about host–parasite relationships and life cycles for these species. Multiple parasites (from one species or from different families of insects) emerged from single cells of some parasitised nests: from each host cell parasitised by species of Pleurochrysis, two adults emerged successfully, information previously unknown for the genus; and in three cases of cells parasitised by C. boutheryi, two adults successfully emerged from a single cell; in two cases both individuals were chrysidine, and in third one was chrysidine and one Leucospis pulchripes (Leucospidae).     

Reproductive phenology and flower visitors' guild of Canistropsis microps (Bromeliaceae) in an Atlantic Rainforest of southeastern Brazil

The reproductive phenology and guild of the floral visitors of Canistropsis microps in an Atlantic Forest area in Ilha Grande, RJ were studied for 4 years. The rates of flowering, fruiting and mortality were related to air temperature, rainfall and photoperiod. To register the flower visitors, observations were carried out for 5 days in each reproductive season. The flowering and fruiting occurred in the rainy season and were positively related to the studied climatic variables, whereas the highest mortality rates occurred in the dry season and were negatively related to the climatic variables. The guild of floral visitors of C. microps was composed of Hymenoptera, characterizing the species as a melittophilous plant. These results indicate that the rainy season presents more favourable conditions for investment in sexual reproduction, besides being the period in which potential pollinators have larger population densities and a longer period of activity.     

Life cycles and host–parasitoid relationships of five species of Leucospis wasps in Argentina (Hymenoptera: Leucospidae)

The genus Leucospis Fabricius is comprised of parasitoid wasps relatively uncommon in nature. Their immature stages develop on aculeate Hymenoptera, in particular solitary bees, but hosts are known for only around 25 Leucospis species (about 20% of 115–120 world species), so the true relationship of this family with bees is largely unknown. Here we report on individuals of five species of Leucospis wasps which emerged from nests of different bee and wasp species during distinct sampling periods during a trap-nesting programme, in two contrasting areas: agro-ecosystems and natural habitats in the Pampean region. Some of these nests were parasitised by L. cayennensis Westwood, L. coxalis Kirby, L. egaia Walker, L. pulchriceps Cameron and L. signifera Bou?ek. Our results expand the available information of host species for L. cayennensis, L. coxalis, L. egaia and L. pulchriceps and represent the first record of hosts associated with L. signifera. The hosts were only bee species of the genera Centris, Tetrapedia (family Apidae) and Megachile (Megachilidae). These species were more abundant in the natural reserve than in agro-ecosystems, suggesting that anthropogenic activities could negatively affect their populations. Most nests were attacked in one (43.7%) or two (40.7%) cells, but the remaining nests (16.5%) had more (up to seven cells). However, the position of the attacked cells was variable, suggesting that females of Leucospis species oviposit in recently built cells, and that the hatching of larvae is delayed, or that the first larval stage waits until the host larva reaches a sufficient size to attack.     

Patterns of insect flower visitation in Lavandula buchii Webb (Lamiaceae), an endemic shrub of Tenerife (Canary Islands)

The foraging ecology of insect visitors of the endemic lavender Lavandula buchii (Lamiaceae) was studied in a relict population of the plant in north-west Tenerife (Canary Islands). Timed observations were used to describe this pollination system in terms of the structure of the visitor assemblage, foraging patterns and efficiencies of the main insect species. The visitor pool was dominated by anthophorid solitary bees. Furthermore, it was characterized by a high level of endemicity and a small number of species compared with continental relatives of Lavandula. The main visitors, two anthophorids and a bombyliid fly, clearly differed in their foraging behaviour, i.e. visitation frequency, visit duration, rate of flower probing, and in anatomical traits (body size and proboscis length). In these terms, the bees were by far more efficient foragers than the fly. These results are discussed in the context of insect-flower interactions in insular pollination systems.     

Nesting behaviour and provisioning in Bembix merceti and Bembix zonata (Hymenoptera: Crabronidae)

We studied the nesting behaviour and provisioning of Bembix merceti Parker and Bembix zonata Klug during three flight seasons (1993–1995). The females of B. merceti capture Diptera from seven different families to feed their larvae. Provisioning is progressive. The females provide a greater number of prey over subsequent days during larval growth. This activity begins increasingly earlier and lasts for longer, and prey capture is increasingly faster. Although the activity of the females is greater during the middle hours of the day, towards the end of each day the number of prey per wasp increases slightly and the duration of provisioning flights is reduced. Regarding Bembix merceti, we also report on nest structure and excavation as well as about the different natural enemies of these wasps. The data recorded for B. zonata refer to nest digging and structure, the wasps' natural enemies and their provisioning strategies, which in general are similar to those seen for the females of B. merceti.     

New species of Australian arid zone chelonine wasps from the genera Phanerotoma and Ascogaster (Hymenoptera: Braconidae) informed by the ‘Bush Blitz’ surveys of national reserves

Here we focus on the poorly studied braconid wasp subfamily Cheloninae for the arid zone of the Australian continent, using material, in part, resulting from comprehensive surveys of three arid zone reserves. The Bush Blitz programme is a multi-institutional project with the aim of documenting the diversity of the flora and fauna in Australia’s National Reserve System, with describing new species being a key focus of the programme. In total, 11 species from the genera Ascogaster and Phanerotoma are treated, with species’ delimitation based on both molecular and morphological data. Two species are redescribed (Phanerotoma behriae Zettel, 1988a and P. decticauda Zettel, 1988a) and nine species are described as new (Ascogaster brevivena sp. nov., A. ferruginegaster sp. nov., A. prolixogaster sp. nov., A. rubriscapa sp. nov., Phanerotoma bonbonensis sp. nov., P. bushblitz sp. nov., P. lutea sp. nov., P. nigriscapulata sp. nov. and P. witchelinaensis sp. nov.). Keys to the arid zone species of these two genera are provided, along with a species richness estimation of Australian chelonine wasps.     

Reproductive phenology and pre‐dispersal seed‐feeding in Protium tovarense (Burseraceae), with a description of the first known phytophagous “Bracon” species (Hymenoptera: Braconidae: Braconinae)

The reproductive phenology of the cloud forest tree Protium tovarense (Burseraceae) is analysed for one population in northern Venezuela. Reproductive phenophases were monitored using both long‐term(21 years) and detailed short‐term (4 years) surveys of flower and fruit set. The reproductive phenology of this tree varies, with periods in which the species behaves as a supra‐annual reproducer, and other periods in which it reproduces annually, at the end of the rainy season. Marked spatial variation in reproductive condition was also observed, with subpopulations separated by less than 2 km showing contrasting phenological stages. Larval infestation of seeds by a braconid wasp was observed for a period of 1 year and is described. This wasp, the first obligately phytophagous species of Braconinae, is described as Bracon phytophagus Quicke sp. n. Percentage fruit infestation by this wasp was relatively high (50–60%) during the entire period (～10 months) of fruit development. The larval stages are described and illustrated, and compared with those of other phytophagous Ichneumonoidea. DNA sequencing of wasp colour variants provided no indication that multiple species were involved. Two related braconine species described in the genus Iphiaulax are transferred to Bracon, hence, B. flavipalpisimus replacement name (Szépligeti) ( = Iphiaulax flavipalpis Szépligeti, 1901 Szépligeti, G v. 1901. Tropische Cenocoeliden und Braconidae aus der Sammlung des Ungarischens National‐Museums.. Természetrajzi Füzetek, 24: 353–402.  [Google Scholar] not B. flavipalpis Thomson, 1892) and B. glabrescens (Szépligeti) n. comb. ( = Iphiaulax glabrescens Szépligeti, 1901 Szépligeti, G v. 1901. Tropische Cenocoeliden und Braconidae aus der Sammlung des Ungarischens National‐Museums.. Természetrajzi Füzetek, 24: 353–402.  [Google Scholar]). Evolutionary routes to phytophagy in braconid wasps and hypothetical scenarios in which this plant–seed predator interaction can be maintained are discussed.     

A new species of the enigmatic Australian endemic family Trachypetidae (Hymenoptera: Ichneumonoidea): Cercobarcon lasallei sp.n.

ABSTRACT

The Trachypetidae is a newly recognised family of Ichneumonoidea endemic to Australia and one of the most distinctive wasp groups on the continent based on their large body size and superficial resemblance to some ichneumonids and aculeate wasps. The family is united in the presence of a unique sensory or glandular structure at the base of the mandibles. It is known from three genera: Cercobarcon Tobias, 1979, Megalohelcon Turner, 1918 (= Rhamphobarcon Tobias, 1979) and Trachypetus Guérin de Méneville, 1830, totalling eight described species. Trachypetines are rarely encountered, with very few specimens having been collected or recognised in collections since the group was revised in 1993. Here we report on a newly discovered species from Cape York Peninsula, Queensland, the first to be recognised in more than 25 years, and take much pleasure in naming it after Dr John La Salle, in celebration of his career.http://www.zoobank.org/urn:lsid:zoobank.org:pub:3F0147A8-F628-4869-B7FD-2E1560145734