336
became associated first with reptiles (e.g. the tick genus Amblyomma) and later—
perhaps in the mid Cretaceous?—other genera underwent a further shift to mammalian hosts; as evidenced by the first example of the typically mammal-associated
genus Haemaphysalis in Burmese amber.
9.5.1 Nest Associates
Irrespective of the timing of this behavioural shift, the modality by which a freeliving species becomes a parasite is also of interest. A free-living predator may,
of course, switch to parasitism directly; see e.g. Weinstein and Kuris (2016) for
a discussion. It is notable that among the acariform mites and the mesostigmatid
mites in general there are many species associated with the nests of birds and
small mammals. It may not require a huge shift from feeding on nest microarthropods or organic material within the nest, to feeding opportunistically and
eventually exclusively on the vertebrates within the nest environment. Intimate
associations with the nest builder also facilitate transfer to new habitats by riding on the larger animal’s body. For a review of this specifically within the
Eleutherengona group and their shift to parasitism on mammals see Bochkov
(2009, and references therein).
9.5.2 From Phoresy to Parasitism
In this context it is also interesting to note how widespread phoresy is among
both acariform and parasitiform mites. To reiterate, phoresy is defined as a commensal relationship, of benefit to the mite but at little or no cost to the host, in
which the mite effectively acts as a ‘stowaway’ attaching itself to a larger animal (reviewed by Binns 1982). Phoresy is typically used for dispersal and/or to
exploit ephemeral sources of food. It is particularly well-developed in the astigmatans (Houck and OConnor 1991), several mesostigmatan lineages (Hunter
and Rosario 1988) and in early-derivative heterostigmatans (Lindquist 1986).
Given that phoresy introduces an intimate relationship between the mite and its
host it is easy to envisage a process by which the mite acquired nourishment
from the host during transport, and eventually came to rely on the host as the
only source of food. A potential model species is the astigmatan Hemisarcoptes
cooremani, which is carried by a beetle, but which also feeds on it during this
transport (Holte et al. 2001). The situation here is complicated by the fact that
the beetle can obtain water from the mite, which suggests a mutualistic relationship rather than parasitism per se.
J. A. Dunlop
became associated first with reptiles (e.g. the tick genus Amblyomma) and later—
perhaps in the mid Cretaceous?—other genera underwent a further shift to mammalian hosts; as evidenced by the first example of the typically mammal-associated
genus Haemaphysalis in Burmese amber.
9.5.1 Nest Associates
Irrespective of the timing of this behavioural shift, the modality by which a freeliving species becomes a parasite is also of interest. A free-living predator may,
of course, switch to parasitism directly; see e.g. Weinstein and Kuris (2016) for
a discussion. It is notable that among the acariform mites and the mesostigmatid
mites in general there are many species associated with the nests of birds and
small mammals. It may not require a huge shift from feeding on nest microarthropods or organic material within the nest, to feeding opportunistically and
eventually exclusively on the vertebrates within the nest environment. Intimate
associations with the nest builder also facilitate transfer to new habitats by riding on the larger animal’s body. For a review of this specifically within the
Eleutherengona group and their shift to parasitism on mammals see Bochkov
(2009, and references therein).
9.5.2 From Phoresy to Parasitism
In this context it is also interesting to note how widespread phoresy is among
both acariform and parasitiform mites. To reiterate, phoresy is defined as a commensal relationship, of benefit to the mite but at little or no cost to the host, in
which the mite effectively acts as a ‘stowaway’ attaching itself to a larger animal (reviewed by Binns 1982). Phoresy is typically used for dispersal and/or to
exploit ephemeral sources of food. It is particularly well-developed in the astigmatans (Houck and OConnor 1991), several mesostigmatan lineages (Hunter
and Rosario 1988) and in early-derivative heterostigmatans (Lindquist 1986).
Given that phoresy introduces an intimate relationship between the mite and its
host it is easy to envisage a process by which the mite acquired nourishment
from the host during transport, and eventually came to rely on the host as the
only source of food. A potential model species is the astigmatan Hemisarcoptes
cooremani, which is carried by a beetle, but which also feeds on it during this
transport (Holte et al. 2001). The situation here is complicated by the fact that
the beetle can obtain water from the mite, which suggests a mutualistic relationship rather than parasitism per se.
J. A. Dunlop