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9.4.2 Parasitiform Mites
As the name implies, the order Parasitiformes includes several parasitic lineages of
mites, although it should be stressed that this is not the lifestyle for the majority of
the species, including the genus Parasitus (see e.g. Rapp 1959) which gives the
group its name. Four main parasitiform clades can be recognised (Fig. 9.3):
Opilioacarida, Holothyrida, Ixodida and Mesostigmata.
9.4.2.1 Opilioacarids
Opilioacarids are rare mites (ca. 40 species) which resemble small harvestmen.
They have been observed feeding on pollen, fungal spores and small arthropods
(Walter and Proctor 1998), and like harvestmen they are capable of ingesting particulate matter. Opilioacarids are known since the Cretaceous (Dunlop and de
Oliveira Bernardi 2014).
9.4.2.2 Holothyrids
Holothyrids are large, dome-shaped mites which appear to be scavengers and have
been recorded sucking haemolymph from dead invertebrates (Walter and Proctor
1998). In this context several authors regard Holothyrida as the sister-group of
Ixodida (e.g. Klompen 2010), and if this phylogeny is correct holothyrid ecology
could offer valuable insights into the blood-feeding origins of ticks. Holothyrids
lack a fossil record.
9.4.2.3 Ticks (Ixodida)
Ticks are probably the most familiar parasitic arachnids, being quite commonly
encountered and of medium to large size. Engorged females of some tropical species can be a couple of centimetres long. About 900 tick species have been described,
all of which are haematophagous ectoparasites of terrestrial vertebrates. Ticks have
attracted a considerable body of research as they are important disease vectors both
for humans and domestic animals. For a general summary of tick biology see
Sonenshine and Roe (2013). More detailed accounts of their phylogeny and evolution can be found in, for example, Estrada-Peña and de la Fuente (2018), Klompen
et al. (1996), Barker and Murrell (2002, 2004), de la Fuente (2003), Nava et al.
(2009) and Mans et al. (2012, 2016). The ecology and epidemiological significance
of ticks was reviewed by Estrada-Peña and de la Fuente (2014), and references
therein.
In brief, ticks have a complex life cycle in which the larva and subsequently the
nymph ingest a blood meal before dropping off and moulting. Adult ticks also feed
J. A. Dunlop
9.4.2 Parasitiform Mites
As the name implies, the order Parasitiformes includes several parasitic lineages of
mites, although it should be stressed that this is not the lifestyle for the majority of
the species, including the genus Parasitus (see e.g. Rapp 1959) which gives the
group its name. Four main parasitiform clades can be recognised (Fig. 9.3):
Opilioacarida, Holothyrida, Ixodida and Mesostigmata.
9.4.2.1 Opilioacarids
Opilioacarids are rare mites (ca. 40 species) which resemble small harvestmen.
They have been observed feeding on pollen, fungal spores and small arthropods
(Walter and Proctor 1998), and like harvestmen they are capable of ingesting particulate matter. Opilioacarids are known since the Cretaceous (Dunlop and de
Oliveira Bernardi 2014).
9.4.2.2 Holothyrids
Holothyrids are large, dome-shaped mites which appear to be scavengers and have
been recorded sucking haemolymph from dead invertebrates (Walter and Proctor
1998). In this context several authors regard Holothyrida as the sister-group of
Ixodida (e.g. Klompen 2010), and if this phylogeny is correct holothyrid ecology
could offer valuable insights into the blood-feeding origins of ticks. Holothyrids
lack a fossil record.
9.4.2.3 Ticks (Ixodida)
Ticks are probably the most familiar parasitic arachnids, being quite commonly
encountered and of medium to large size. Engorged females of some tropical species can be a couple of centimetres long. About 900 tick species have been described,
all of which are haematophagous ectoparasites of terrestrial vertebrates. Ticks have
attracted a considerable body of research as they are important disease vectors both
for humans and domestic animals. For a general summary of tick biology see
Sonenshine and Roe (2013). More detailed accounts of their phylogeny and evolution can be found in, for example, Estrada-Peña and de la Fuente (2018), Klompen
et al. (1996), Barker and Murrell (2002, 2004), de la Fuente (2003), Nava et al.
(2009) and Mans et al. (2012, 2016). The ecology and epidemiological significance
of ticks was reviewed by Estrada-Peña and de la Fuente (2014), and references
therein.
In brief, ticks have a complex life cycle in which the larva and subsequently the
nymph ingest a blood meal before dropping off and moulting. Adult ticks also feed
J. A. Dunlop