1,720,997 research outputs found
Un modello matematico di interazione parassita - ospite : applicazione al caso Gordius villoti Rosa (Nematomorpha) e Allogamus auricollis Pictet (Trichoptera)
No full textSearching for the right target: oviposition and feeding behaviour in Bombylius bee flies (Diptera: Bombyliidae)
No full textBee flies (Diptera: Bombyliidae) are ectoparasitoids of larval stages of insects, often digger bees and wasps. We studied the behavior of 4 species of the genus Bombylius at a nest aggregation of their host bee, Lasioglossum malachurum Kirby, and at an adjacent feeding site. Although eggs were frequently thrown on vegetation patches, the number of eggs oviposited and the time spent in hovering flight were higher at host nest entrances. Bombylius females fed essentially on 3 (2 Caryophyllaceae and 1 Asteraceae) of 9 blooming plant species found in the area. Oviposition and feeding activities had different daily distributions. In general agreement with optimal foraging theories, Bombylius females exhibited the strongest interest in the predicted target, i.e., the host nest, and fed essentially on a few but highly exploited plants in the close vicinity of the host nesting site
A note on the host detection by Buathra tarsoleuca (Schrank) (Hymenoptera: Ichneumonidae), a parasite of Ammophila sabulosa (L.) and Podalonia affinis (Kirby) (Hymenoptera: Sphecidae)
No full textAssociation of the scuttle fly Megaselia leucozona Schmitz (Diptera: Phoridae) with sweat bees (Hymenoptera: Halictidae), with a description of the male fly
No full textMegaselia leucozona Schmitz (Diptera, Phoridae) is reported from nests of
Lasioglossum malachurum Kirby and Halictus scabiosae (Rossi) in Central Italy.
The flies patrolled twonesting sites of the hosts and sometimesmated close to
their nest entrances before entering. Observations agree with the general behaviour reported for other Megaselia species associated with fossorial bees and
wasps. The hitherto unknownmale of M. leucozona is described, and the original
description of a female is augmented and modified. This is the first report of a
scuttle fly associated with nests of Halictidae in the Palaearctic Region
Some behavioural observations on Megaselia oxybelorum (Diptera: Phoridae), a new kleptoparasite of Cerceris arenaria (Hymenoptera: Sphecoidea: Philanthidae)
No full textTemporal transition of nesting activities in the digger wasp, Bembecinus tridens (Hymenoptera: Crabronidae)
No full textA nest aggregation of Bembecinus tridens (Hymenoptera: Crabronidae) was investigated through observations of marked individual females in Northern Italy, in order to quantify frequencies, duration, and sequence of the nesting activities. Wasp females dug unicellular (in one case multicellular) nests preferably on oblique surfaces. Nest digging occurred mainly in the morning, while definitive nest closing was performed only in the afternoon, and nests were frequented by the owners for 3.52 days on average. One to eight nests were dug by single females in rapid succession in the area observed, revealing a rapid dispersion towards other sites. Provisioning and non-provisioning (control) flights were positively correlated and occurred mainly in the late morning. A number of orientation flights followed most exits from the nests but was higher at the end of nest digging. Nest closing lasted more at the end of provisioning and at the end of digging. Provisioning began more frequently one day after nest digging (and oviposition), less frequently two days after, and the number of prey per day was negatively correlated with the number of provisioning days. Data are consistent with a situation of primitive progressive provisioning, and match that of other species of the same genus
Prey spectrum and predator-prey size relationship of the solitary wasp, Trachypus denticollis, in central Chile (Hymenoptera: Crabronidae)
No full textNeotropical solitary bee-hunting wasps of the genus Trachypus (Hymenoptera: Crabronidae) are ecologically and behaviourally little known. Here, we report information on prey types used by the digger wasp Trachypus denticollis Spinola in central Chile. Female wasps hunted at least 12 species of prey in five families, with Halictidae the most commonly represented. Brood cells are filled with one to eight prey. Cells with greater numbers of prey contained fewer species than expected, suggesting a temporal constancy in individual prey use. A positive linear relationship exists between the number of prey stored in a cell and their total biomass. Larger females tended to collect larger bees than did smaller females; however, because wasp and prey size distributions did not overlap, small wasps may be not constrained to a narrower prey spectrum compared to large ones. We conclude that prey size is an important factor determining prey use in T. denticollis, and these findings match that observed for species of the sister beewolf genus Philanthus and other philanthine wasps
Evidence of entrance sharing and subterranean connections in Andrena agilissima (Hymenoptera; Andrenidae)
No full textNesting habits of two spider wasps: Anoplius infuscatus and Episyron sp. (Hymenoptera: Pompilidae), with a review of the literature
No full textMany behavioural aspects of Anoplius infuscatus (Vander Linden) and Episyron sp. Schioedte were examined in detail, both on a qualitative and, when possible, on a quantitative level, during a long-term field study in Northern Italy. Both wasps dig unicellular nests on bare soil, which are filled with a single spider to feed the brood. The main differences regard the way to hunt their prey, that of burrowing, that of transporting and introducing the spider into the nest, the habit of amputating spider legs and the abdominal movements during nest closing. On the whole, starting from prey capture to nest closure, A. infuscatus is significantly slower than Episyron. The observed ethological differences are well fitted to the exploitation of the different preys consisting in wolf spiders (Lycosidae) and orb weaving spiders (Araneidae), respectively. Some flexibility in the observed behaviour is described. A critical re-examination of the literature shows that, even if most results agree with those of previous authors, two controversial points remain open regarding. Episyron species: the position of the egg (on the prey or on the cell wall) and the way to grasp the spider during tranport and introdution into the nest
Factors affecting spider prey selection by Sceliphron mud-dauber wasps (Hymenoptera: Sphecidae) in northern Italy
No full textPredatory habits of apoid wasps are well documented for many species, revealing a choice of prey ranging from generalist to specialised, but few studies tested the degree of specialisation when compared with the availability of prey in the environment. In a study carried out in northern Italy, nests of the mud-dauber wasps Sceliphron spirifex L. and S. caementarium Drury were collected to obtain
the spider prey of the wasps, and a survey of the nesting area was performed to ascertain frequency of the available spider prey species in the environment. Wasps preyed preferably upon spiders of the
family Araneidae. Adult preferred spider prey size ranged from 4 to 6 mm in length. The factor which most affected prey selection was the ecology of the spiders, with orb-web spiders being the preferred
prey despite the fact that terricolous, non-web groups were the most abundant in the locality. Sex (female, male or juvenile) of prey was also important in prey selection: juvenile spiders were the most preferred even though males and females were equally and most abundant (respectively). Sceliphron
spp. seem almost to be specialised rather than generalist predators. These results suggest that the terms ‘generalist’ or ‘specialised’ should not be applied to predators solely on the basis of prey collected from wasp nests, but should also be related to local prey availability
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