Eviphididae

Mašán, Peter & Halliday, Bruce, 2010, Review of the European genera of Eviphididae (Acari: Mesostigmata) and the species occurring in Slovakia 2585, Zootaxa 2585, pp. 1-122 : 9-10

Ecology of Eviphididae

Feeding behaviour. The Eviphididae are widely quoted as being predatory, especially as predators of nematodes, but other possible prey have been mentioned, including insect eggs and larvae. However, direct evidence of feeding behaviour is available for only a few species. Sardar & Murphy (1987) and Murphy & Sardar (1991) showed that Alliphis halleri fed and reproduced on a diet of three species of nematodes, but did not feed on mites, Collembola, enchytraeid worms, or insect eggs and larvae when they were offered to it. These results support the statements by Karg (1971, 1983) that A. halleri is a specific predator of nematodes. Karg & Grosse (1983) extended this observation to show that A. halleri (referred to as A. siculus ) can have a beneficial effect by feeding on pest nematodes in agricultural crops. Walter et al. (1988) also found that species of Alliphis , Eviphis and Crassicheles fed on nematodes but did not take other types of food. Walter & Proctor (2001) reported that Evimirus , Eviphis and Alliphis feed on nematodes in soil, Egglishaw (1965) observed Thinosieus fucicola feeding on nematodes in beach wrack, and Christie (1983) found that Alliphis necrophilus thrived on a diet of nematodes of the genus Panagrellus . All the available evidence indicates that Eviphididae are predators of nematodes.

General ecology. Evans (1969) divided the Eviphididae into two main ecological groups, consisting of (1) non-phoretic species that occur in stable continuous habitats such as soil and forest litter, and (2) species that occur in temporary patches of organic matter such as dung, and which disperse by phoresy on various insects. The second of these categories actually covers a wide range of different life history strategies. We can distinguish between species that have only a brief phoretic relationship with their insect carriers, and those that spend all or most of their life cycle on a host insect or in its nest. According to these microhabitat requirements and phoretic behaviour, 18 of the 19 species of Eviphididae in Slovakia can be classified into the following groups (see Table 1). We cannot include Uroseius montivagus in this classification because we only have two specimens from a single collection.

(A) Edaphic detriticoles (four species, representing 22% of recorded species). This group consists of soilinhabiting species, either early derivative ancestral forms ( Halolaspis hypedon , Pseudoalliphis sculpturatus and Rafaphis microsternalis ), or highly derived forms ( Eviphis ostrinus ) which may be considered to be a secondary inhabitant of soil substrates. These species are non-phoretic, and all occur in monotypic genera. They can be found in leaf and pine needle litter, raw humus, and various kinds of soil substrates and litter.

(B) Sapro-coprophiles (five species, representing 28% of recorded species) include species showing a strong affinity for decaying organic substrates such as dung and plant remains. They can occur in other transient substrates that include a proportion of dung or decaying organic matter (manured arable soils, nests, mixed organic refuse). Some of these species are able to rapidly colonise fresh dung with a high content of water and nitrates. This group includes species with well-developed phoretic activity, either non-specific on various coprophilous insects ( Alliphis halleri ) or specifically associated with sphaerocerid flies and staphylinid beetles ( Crassicheles striatus , Neocrassicheles sternomus and Uroiphis spp. ).

(C) Insecticoles (the most numerous group, with nine species, representing 50% of recorded species). This ecological group includes species that spend all or part of their life cycle on a host beetle or in its nest. Among them are non-specific species that exploit a wide variety of coprophagous Scarabaeoidea, as well as species that are highly specific to one host, or several closely related hosts. True insecticolous species stay on the host during almost their whole life cycle, and immature as well as adult stages can be found on the insect host. These species do not appear to actually reproduce on the host insect, and no larvae or protonymphs are present while the host is not reproducing. The life cycle of these mites is closely bound with that of the host. They usually do not leave the host adult beetles or their nests, and they occur only sporadically and accidentally unattached to the specific host phoronts in the dung microhabitat. Specimens from this group are rare in Tullgren funnel extracts from dung pads, and we have never found them in dung heaps or rotting vegetable matter. The geographical distribution of the insecticoles depends closely on the distribution of the host insects. These species are mostly coprophilous associates of coprophagous scarab beetles, except for Alliphis kargi , which is associated with the phytophagous geotrupid Lethrus apterus , and Alliphis necrophilus , an associate of necrophagous burying beetles of the genus Nicrophorus (Silphidae) . The development of insecticolous eviphidids does not depend wholly upon the presence/absence of suitable substrate, but rather upon the ontogeny and nesting behaviour of the host beetles.

sional, – = not recorded).

Interspecific associations. The mite species classified into groups B and C above occur in scattered patchy habitats and depend on phoresy on insects to disperse from one habitat patch to another. Different species of Eviphididae are phoretic at different stages of their life cycle, as summarised in Table 2. In the most common type of phoresy, adult females, adult males, and deutonymphs are all phoretic. This behaviour is found in Scarabaspis inexpectatus and all four species of Alliphis . In the second type of phoresy it appears that only males and deutonymphs are phoretic. This behaviour is characteristic of Alloseius pratensis , Crassicheles striatus , Neocrassicheles sternomus , Pelethiphis opacus , and Uroiphis greeni . The phoretic deutonymphs of U. greeni moult to adults soon after they arrive at a fresh dung pad, but the adult females have a short life span and do not leave the dung pad ( Makarova 1993, 1994). The female of P. opacus remains unknown, so it is included in this group only provisionally. In Copriphis pterophilus and Scarabacariphis ankavani both male and female adults are phoretic, in Scamaphis equestris only the adult females (although the male is unknown), and in Uroiphis scabratus only the deutonymphs are phoretic. This wide variety of different phoretic strategies in the family Eviphididae reflects variation in the nature of the relationship between the mites and their host insects. The insects that carry Eviphididae are mainly coprophilous beetles and flies, as summarised below. This list of Eviphididae and their insect carriers is derived from published records and our new observations, all from Slovakia.