Milichiidae | |
---|---|
Adult of a Paramyia species | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Diptera |
Section: | Schizophora |
Subsection: | Acalyptratae |
Superfamily: | Carnoidea |
Family: | Milichiidae Schiner, 1862 |
Subfamilies | |
Milichiidae are a family of flies. Most species are very small and dark. Details of their biology have not yet been properly studied, but they are best known as kleptoparasites of predatory invertebrates, and accordingly are commonly known as freeloader flies or jackal flies. [1] However, because of the conditions under which many species breed out, they also are known as filth flies. [2]
The Milichiidae are a family of flies in the suborder Brachycera. They were at one time included in the family Carnidae. At one time or another they have been assigned to various superfamilies, including Carnoidea, Chloropoidea, [3] and Agromyzoidea. [4] As usual for flies of these groups, Milichiidae imagines are tiny, but their heads are comparatively large, compared to many fly species of the same size, such as those in the family Phoridae. [5]
Milichiidae are small-to-very-small flies, usually 1 to 3 mm in length. Typically they are black or at least dark. In some species, such as Milichiella argyrogaster, the abdomen of the male is silvery on its dorsal surface because of a covering of fine hairs. [6] [7] The eyes of Milichiidae are often red, though this need not be obvious because many species of the flies are small and dusky. Though the proboscis is fairly long in most species, this is not obvious because it commonly is geniculate, having a knee-like fold in the middle that holds it inconspicuously beneath the head when the animal is not feeding. When it is looking for a place to feed on the prey of a spider or the like, the proboscis is extended, giving an impression of licking, as shown in the accompanying video. The abdomen is short and broad; it may be impressively distended after a large meal, as shown in the accompanying photographs.
The larval stage generally lasts about 2–3 weeks in temperate climates. Larvae primarily feed on rotting vegetable matter or decaying wood or bark and may be reared from manure or decaying plant materials. At least some are coprophagous and feed on human ordure and other detritus, hence the common name "filth flies". [2] At least some species may breed in dead fish and other carrion, a point of possible interest in forensic entomology. [8]
Some species also have been recovered or reared from birds' nests and bat roosts, but reports of parasitism on birds' nestlings by Milichiidae should be interpreted with caution; at one time Milichiidae and Carnidae were not regarded as separate families, and it is not always clear how many of such reports refer to any species other than those that nowadays are included in the Carnidae and separated from the Milichiidae. [9]
Human commerce has inadvertently spread some species to all continents but Antarctica. Examples include members of the genera Desmometopa and Milichiella. [6]
The adults of some species linger close to invertebrate predators, where they act as kleptoparasites, feeding on bodily fluids of the prey. This strategy has given rise to a range of common names such as freeloader flies and jackal flies. The nature of the kleptoparasitism that Milichiidae practise is difficult to detect from direct observation; some observers remark that they seem to lick the prey rather than anything else. [10] [11] However, it seems that they get whatever nourishment they can; the accompanying photographs suggest that at least some species penetrate the thinnest cuticle of a bee in a spider's jaws, extracting tissues that enzymes in the venom of the spider have reduced to a fluid state. [12] When extended, the proboscis certainly is long enough for feeding in such a manner. [6]
The "jackal" habit has been widely documented, with many pictures and references to Millichiidae assembling on the prey of spiders (especially Nephilinae, Oxyopidae, and Thomisidae). They also visit Asilidae, Reduviidae, and even Mantodea. However, a point that is rarely mentioned is that most prey insects do not attract Milichiidae particularly. Instead they seem only to follow the scents exuded by killed prey such as Hemiptera, Heteroptera (stink bugs), and Hymenoptera. [13] This is compatible with the fact that photographs of Milichiidae on prey, almost universally show them on insects that provide such olfactory clues. This would be compatible with the idea that predators that commonly hunt prey that release a dramatic and characteristic olfactory signal, thereby create a niche for suitable kleptoparasites. [14] In at least species that are attracted to prey of Nephilinae in Florida, the major attractants released by Heteropteran prey appear to be low-molecular-weight carbonyl compounds, among which trans-2-hexenal and hexanal are prominent. These compounds are not conspicuous among those released by captured honeybees, so other classes of attractants are likely to be significant as well. [13] In general there is suggestive evidence that the kleptoparasitism relies on olfactory clues; for example, some species seem to operate in the dark, and photographs of approaching flies seem to show them flying upwind, which is consistent with scent following. [14]
A notable point is that spiders' meals can have various forms of significance in nature. For one thing, though they may be the most conspicuous of such partakers, the jackal habit is not unique to the Milichiidae, nor do all species in the family necessarily indulge in it, nor for all the same reasons. Certainly careful inspection of photographs of spiders' prey often will show a few specimens from other families of small flies present among the Milichiidae. Examples include Phoridae and Chloropidae. [13] [15] [16] The high frequency of Milichiidae around prey of particular species however, suggests that they are more highly adapted to such activities than most. However, this impression might be regional; reports on field work suggest that in parts of Florida for example, the predominant kleptoparasites were in the family Cecidomyiidae. However, dedicated investigation revealed an impressively wide range of visitors, including Ceratopogonidae and Phoridae. [14] The attraction of the aromas of feeding female spiders, and even of promising sites for female ambushes, also extends to male crab spiders Thomisidae of some species, but in their case the function of the attraction is likely to be reproduction rather than nourishment. [17] [18] [19] Most kleptoparasitic Michiliidae are females, the males presumably having a lower requirement for proteinaceous food; however, as inferred in from the apparent presentation of droplets of food from the proboscises of gorged females, it is possible that the presence of females at the spiders' meals might be reason for males to assemble as well. [14]
Another activity observed in some species of Michiliidae, shows them to be serving a function analogous to that of cleaner wrasse and cleaner shrimp; they literally scavenge around the chelicerae and anal openings of large spiders, such as species of Araneus and Nephila, that cooperatively spread their wet and sticky chelicerae thus allowing the flies to feed actively all over the bases, fangs and mouth. [20] [21]
Some Michiliidae act in various roles as kleptoparasites of various ants. [22]
Subfamily Madizinae
Subfamily Milichiinae
Subfamily Phyllomyzinae
Flies are insects of the order Diptera, the name being derived from the Greek δι- di- "two", and πτερόν pteron "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced mechanosensory organs known as halteres, which act as high-speed sensors of rotational movement and allow dipterans to perform advanced aerobatics. Diptera is a large order containing an estimated 1,000,000 species including horse-flies, crane flies, hoverflies, mosquitoes and others, although only about 125,000 species have been described.
Kleptoparasitism is a form of feeding in which one animal deliberately takes food from another. The strategy is evolutionarily stable when stealing is less costly than direct feeding, such as when food is scarce or when victims are abundant. Many kleptoparasites are arthropods, especially bees and wasps, but including some true flies, dung beetles, bugs, and spiders. Cuckoo bees are specialized kleptoparasites which lay their eggs either on the pollen masses made by other bees, or on the insect hosts of parasitoid wasps. They are an instance of Emery's rule, which states that insect social parasites tend to be closely related to their hosts. The behavior occurs, too, in vertebrates including birds such as skuas, which persistently chase other seabirds until they disgorge their food, and carnivorous mammals such as spotted hyenas and lions. Other species opportunistically indulge in kleptoparasitism.
The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking to the wing. This behaviour is a source of one of their alternate names, scuttle fly. Another vernacular name, coffin fly, refers to Conicera tibialis. About 4,000 species are known in 230 genera. The most well-known species is cosmopolitan Megaselia scalaris. At 0.4 mm in length, the world's smallest fly is the phorid Euryplatea nanaknihali.
The Asilidae are the robber fly family, also called assassin flies. They are powerfully built, bristly flies with a short, stout proboscis enclosing the sharp, sucking hypopharynx. The name "robber flies" reflects their expert predatory habits; they feed mainly or exclusively on other insects and, as a rule, they wait in ambush and catch their prey in flight.
The Acroceridae are a small family of odd-looking flies. They have a hump-backed appearance with a strikingly small head, generally with a long proboscis for accessing nectar. They are rare and not widely known. The most frequently applied common names are small-headed flies or hunch-back flies. Many are bee or wasp mimics. Because they are parasitoids of spiders, they also are sometimes known as spider flies.
Carnoidea is a superfamily of Acalyptratae flies.
Nepenthesinfauna are the organisms that inhabit the pitchers of Nepenthes plants. These include fly and midge larvae, spiders, mites, ants, and even a species of crab, Geosesarma malayanum. The most common and conspicuous predators found in pitchers are mosquito larvae, which consume large numbers of other larvae during their development. Many of these animals are so specialised that they cannot survive anywhere else, and are referred to as nepenthebionts.
Misumena vatia is a species of crab spider with a holarctic distribution. In North America, it is called the goldenrod crab spider or flower (crab) spider, as it is commonly found hunting in goldenrod sprays and milkweed plants. They are called crab spiders because of their unique ability to walk sideways as well as forwards and backwards. Both males and females of this species progress through several molts before reaching their adult sizes, though females must molt more to reach their larger size. Females can grow up to 10 mm (0.39 in) while males are quite small, reaching 5 mm (0.20 in) at most. Misumena vatia are usually yellow or white or a pattern of these two colors. They may also present with pale green or pink instead of yellow, again, in a pattern with white. They have the ability to change between these colors based on their surroundings through the molting process. They have a complex visual system, with eight eyes, that they rely on for prey capture and for their color-changing abilities. Sometimes, if Misumena vatia consumes colored prey, the spider itself will take on that color.
Carnidae, also known as bird flies or filth flies, is a family of flies (Diptera). There are 6 genera, containing about 93 species worldwide.
Bombylius major is a parasitic bee mimic fly. B. major is the most common type of fly within the Bombylius genus. The fly derives its name from its close resemblance to bumblebees and are often mistaken for them.
Diptera is an order of winged insects commonly known as flies. Diptera, which are one of the most successful groups of organisms on Earth, are very diverse biologically. None are truly marine but they occupy virtually every terrestrial niche. Many have co-evolved in association with plants and animals. The Diptera are a very significant group in the decomposition and degeneration of plant and animal matter, are instrumental in the breakdown and release of nutrients back into the soil, and whose larvae supplement the diet of higher agrarian organisms. They are also an important component in food chains.
Carnus is a genus of flies (Diptera) with 5 described species, all of which are parasites of birds. The adult flies locate a suitable host nest, then shed their wings and feed on the blood of the developing nestlings. Mature female flies lay their eggs in the nest, where their larvae develop on organic detritus.
Hemeromyia is a genus of flies (Diptera).
Pollination traps or trap-flowers are plant flower structures that aid the trapping of insects, mainly flies, so as to enhance their effectiveness in pollination. The structures of pollination traps can include deep tubular corollas with downward pointing hairs, slippery surfaces, adhesive liquid, attractants, flower closing and other mechanisms.
The Chloropidae are a family of flies commonly known as frit flies or grass flies. About 2000 described species are in over 160 genera distributed worldwide. These are usually very small flies, yellow or black and appearing shiny due to the virtual absence of any hairs. The majority of the larvae are phytophagous, mainly on grasses, and can be major pests of cereals. However, parasitic and predatory species are known. A few species are kleptoparasites. Some species in the genera Hippelates and Siphunculina are called eye gnats or eye flies for their habit of being attracted to eyes. They feed on lachrymal secretions and other body fluids of various animals, including humans, and are of medical significance.
Ireangelus is a genus of kleptoparasitic spider wasps from the sub-family Ceropalinae of the family Pompilidae. The genus has a pan tropical distribution, being known from Oriental, Neotropical, Australian, eastern Palearctic, and Madagascan Zoogeographic regions being best represented in the Neotropics. Irenangelus is closely related to the more widespread genus Ceropales, the two genera forming a monophyletic subfamily, Ceropalinae within the Pompilidae. This is regarded as the most basal grouping of the Pompilidae but this view is problematic because of the kleptoparasitic life history of the Ceropalines, it is now considered that they Ceropalines and other pompilids evolved from a common ectoparasitoid ancestor.
Milichiella is a genus of freeloader flies in the family Milichiidae.
Argyrodes elevatus, commonly referred to as dew-drop spider, is part of the family Theridiidae that consists of more than 3,000 species. These spiders are most commonly found in subtropical and tropical regions in South and Central America, as well as southern regions of the United States. One of the key distinguishing characteristics of A. elevatus is its kleptoparasitic behavior through which it primarily procures food for survival. Typically 1 or 2 A. elevatus spiders preside in outer areas of webs built by other species of spiders, although it is possible for up to 45 spiders. There are two main mechanisms by which A. elevatus raid the hub of the host's web to steal insects preyed and wrapped by the host spider. A. elevatus follows an intricate course to the hub of the web to search for prey, using vibrational detection enhanced by laid out threads along the web to find and capture the insect. These spiders are highly efficient, with the theft lasting a maximum of 12 seconds and high success rates. This reliance on a host spider for food has led to adaptations in sleep schedules and alternate food sources to revolve around the host species activity. A. elevatus display a unique courtship routine in which male A. elevatus presents prey wrapped in silk as a nuptial gift to the female spider. The male spider approaches the female, carrying the nuptial gift on its chelicerae while communicating with a distinct courting vibration, followed by copulation. Approximately twenty-four hours after the A. elevatus courtship and copulation series of events, the female spider will lay one to two eggs on the outer regions of the host's web.
Thomisus spectabilis, also known as the white crab spider or Australian crab spider, is a small spider found in Australia and far east Asia.
Toxomerus basalis, commonly known as the sundew flower fly, is a species of kleptoparasitic fly endemic to Brazil. It was first described by Francis Walker in 1836. It feeds on captured, immobilized insects caught on the sticky leaves of sundew plants, which are carnivorous. Adult flies seem to have some capacity to escape from Drosera leaves if they have not come into contact with too many of the tentacles. The species is non-specific and have been found on large-leaved, semi-erect, and thread-like Drosera species, such as Drosera graomogolensis and Drosera magnifica.