Research done by ARC-PPRI has shown that a variety of spiders
are predators of the harvester termite, Hodotermes mossambicus (Hagen
1858) in Southern Africa. Harvester termites forage in sporadic bursts of
activity on the soil surface from their subterranean nests. When present in high
numbers they can cause severe damage to grassland, especially during long
periods of drought. One of the most important predators are members of the
family Ammoxenidae of the genus Ammoxenus. The ammoxenid spiders are free-living soil-dwellers, also known
as sand divers due to their ability to dive headfirst into sand when disturbed.
They are only known only from southern Africa, with six described species
occurring throughout the region. They are commonly found in high numbers in
areas infested with harvester termites. Ammoxenus species are regarded
as specialist predators of the harvester termites. They are invariably found in the soft soil mounds left after
excavation by the termites in close proximity to the nest entrance. They are
able to detect termite foraging activity either through soil vibration or
chemical cues. The spiders use tactile cues to select suitable prey items after
initially handling of the prey. During prey capture, the termite is grabbed and
bitten between the head capsule and the cephalothorax. The dead termite is
pulled below the soil surface by the spider before feeding commences. Prey is
sucked out and not chewed. They spend inactive periods in sac-like retreats made
in the soft soil humps, left by the termites during excavations of their
subterranean nests. Along with the retreat sacs, other soft silk sacs containing
dead harvester termites (4-8 termites per sac) were collected from the soil
mounds. It appears that these termites might serve as a food reserve for the
spiders during the long periods when the termites are inactive. Harvester
termites display erratic bursts of activity. The ammoxenids are able to detect
these busts whether they occur nocturnally or diurnally. The termites are thus
available sporadically for short periods, above ground for the spiders to catch.
The termite workers are either killed, pulled immediately below the soil surface
and fed upon or they are paralyzed and stored in silk sacs just below the soil
surface for feeding at a later stage. Further reading:Dippenaar, A.S. & M.K.P. Meyer. 1980. On
the species of the African genus Ammoxenus (Araneae: Ammoxenidae), with
descriptions of two new species. Journal of the Entomological Society of
Southern Africa 43:41-49. Dippenaar-Schoeman, A.S., M. de Jager & A. van den
Berg. 1996a. Behaviour and biology of two species of termite-eating
spiders, Ammoxenus amphalodes and A. pentheri (Araneae: Ammoxenidae), in South
Africa. African Plant Protection 2:15-17. Dippenaar-Schoeman, A.S., M. de Jager & A. van den
Berg. 1996b. Ammoxenus species (Araneae: Ammoxenidae) - specialist
predators of harvester termites in South Africa. African Plant
Protection 2:103-109. Dippenaar-Schoeman, A.S. & Harris, R.
2005. Food storage by a wandering ground spider (Araneae, Ammoxenidae,
Ammoxenus). Journal of Arachnology 33: 850-852. Van den Berg, A. & A.S. Dippenaar-Schoeman.
1991. Ground-living spiders from an area where the harvester termite
Hodotermes mossambicus occurs in South Africa. Phytophylactica
23:247-253. Research on other speciesHaddad, C.R. & Dippenaar-Schoeman, A.S. 2006. Spiders (Araneae) inhabiting abandoned mounds of the snouted harvester termite Trinervitermes trinervoides (Sjöstedt) (Isoptera: Termitidae: Nasutitermitinae) in the Free State, South Africa, with notes on their biology. Navorsinge van die Nasionale Museum, Bloemfontein22: 1-15. |  Ammoxenus sp. feeding on termite
 Ammoxenus sp. also known as sand divers
 Egg
sacs
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