Oi David H, Williams David F
USDA-ARS Center for Medical, Agricultural, and Veterinary Entomology, Gainesville, FL 32608, USA.
J Econ Entomol. 2002 Jun;95(3):558-62. doi: 10.1603/0022-0493-95.3.558.
Three studies were conducted to assess the effects of the entomopathogen Thelohania solenopsae on polygynous, red imported fire ant, Solenopsis invicta Buren, colonies. A total of 57 of 122 queens (46.7%) from nine, field-collected, polygyne, S. invicta colonies, was infected with T. solenopsae. Infection rate of queens for each colony ranged from 25 to 75%. Laboratory colonies of polygyne S. invicta, with three to 12 queens, were inoculated and infected with T. solenopsae. Brood levels in all infected colonies declined to 0 after 26-52 wk. Brood did not reappear in any of the colonies after 3-11 wk, even though in two of the eight infected colonies, five fertile queens that were uninfected were recovered. Thus, polygyne, S. invicta colonies infected with T solenopsae, which were confined and isolated under laboratory conditions, did not recover. Field plots that contained polygynous S. invicta colonies, which were infected with T solenopsae, were monitored over a 2-yr period. Infection rates increased during the study and reached a maximum of 9.3%. Fire ant nest density and colony sizes fluctuated over time, with maximum reduction of 63% per plot. In general, fire ant reductions were attributed to smaller colony sizes. T. solenopsae infections in polygynous S. invicta can result in a slow colony decline and death. Under field conditions, the prolonged colony death may mask the impact of T. solenopsae by allowing for concurrent reinfestations.
开展了三项研究，以评估昆虫病原体索氏泰勒蚁对多蚁后型红火蚁（Solenopsis invicta Buren）蚁群的影响。从9个野外采集的多蚁后型红火蚁蚁群中总共选取了122只蚁后，其中57只（46.7%）被索氏泰勒蚁感染。每个蚁群中蚁后的感染率在25%至75%之间。将含有3至12只蚁后的多蚁后型红火蚁实验室蚁群接种并感染索氏泰勒蚁。26至52周后，所有受感染蚁群中的幼虫数量降至0。3至11周后，所有蚁群中均未再出现幼虫，尽管在8个受感染蚁群中的2个中，发现了5只未受感染的可育蚁后。因此，在实验室条件下被限制和隔离的、感染了索氏泰勒蚁的多蚁后型红火蚁蚁群未能恢复。对含有感染了索氏泰勒蚁的多蚁后型红火蚁蚁群的野外地块进行了为期两年的监测。在研究期间感染率上升，最高达到9.3%。红火蚁巢穴密度和蚁群大小随时间波动，每个地块最多减少63%。一般来说，红火蚁数量减少归因于蚁群规模变小。多蚁后型红火蚁被索氏泰勒蚁感染会导致蚁群缓慢衰退和死亡。在野外条件下，蚁群长时间死亡可能会因同时发生的再次侵染而掩盖索氏泰勒蚁的影响。
