The Ecology of Tijuana Estuary, California: An Estuarine Profile

Figure 31. The salt panne insects include several species of rove beetle (5lsdrus: Coleoptera: Staphylinidae. on
left), t~ger beetle (adult shown in center is Crcrndek gabbr: larva is C oregona; Coleoptera: Cicindelidae), and
bugs. The saldid bug (Pentacofa stgnoreti; Hemiptera: Saldidae, 8 mm long), a very important predator, is abundant
on all salt and mudflats from lower t~ hlgher marsh. Mclntire collection, copyrrght 1986 by Zedler.
to the beetles during hrgh tide In studies of a consrdered benefic~al Tiger beetles are preyed
Scandinav~an species of Bledrus, Larson (1953) upon by other salt panne and trdat flat Insects
found that these rove beetles evacuated tunnels including robber flies (Dtptera Asrlidae) and
durlng hrgh trde and could be found beneath debris dragonfiles (Odonata Anrsoptera), and numerous
at the wrack l~ne during such perrods Thrs did not vertebrates such as brrds, reptiles, and mammals
occur at Trjuana Estuary Very few beetles were (D Mclntire, naturalist, pers comm )
ever observed outside a burrow, regardless of trdal
cycle Tiger beetles are constdered to be good
rndrcators of the disturbance to coastal systems
Some lnsects that inhabrt the salt pannes are (Nagano 19821, the least drsturbed habitats have
considered "threatened " Threatened specres are several specles of tiger beetles Although
those whose range is declfntng due to loss of quant~tatrve data from the period before closure of
habrtat and/or have been proposed as candidates the estuary mouth are lacking, qualitative estimates
for State or Federal lrstrng Among such Insects ~ndrcate that populations increased srgn~ficanliy
are the trger beetles (genus Ctctndeta) Tijuana after the mouth was reopened (Mclntrre. pers.
Estuary supports the highest drvers~ty and comm )
abundance of trger beetles of any coastal locallly
in southern California and posslbly all of Calrfornia Another group of insects that can be regarded
(C Nagano, uc Santa Barbara M ~ pers ~ as good ~ indicators ~ of ~ disturbance , are the true bugs
comm) There are at least four species of this of the order Hemrptera, famrly Saldidae Several
genus that occur here, two of which rnhabrt the salt of ti-~es@ rnsects occur on the least disturbed
pannes, although they have been observed there salt Pannes They have a *lde salintf~ tolwance
only rn low numbers These are the mudflat tiger and are carnrvorous, feed~ng on sprrngtarls, mites,
beetle (Ciondela tr,fascfata s,grnoidea) and Gabb's and ~tfler msects arid spiders On@ member of this
ttger beetle (C gabb~, Figure 31 )
fam~ly, Penfacara stgnorel~ (Figure 31), IS very
abundant at Trjuana Estuary lndrvrduals coated
Tiger beetles are predaceous, they feed upon with salt CrUPt have been observed Qn salt PanneS.
any arthropods they can overpower Adults are but the fnechanlsm far tolerat'ng such high
found on rnud or sand near permanent bodies of salrnttles IS not known (Mclntire, pers comm f
water Larvae knhabll burrows ln the soil In the
same area as the adults The larvae (F~gure 31) Salt pannes are often used as foraging areas for
are also predaceous. ustng hooklike mandibles to Beldrng's Savannah sparrows, which feed on the
capture and kill their prey, which IS then consumed insects there Calrfornia least terns and snowy
w~thin the burrow, Because their prey includes plovers are both known to nest on salt pannes
rnsects that are harmful to man, these beetles are Both species use preformed depressrons, such as
3 1