The ecological role of ants in two Mexican agroecosystems

Abstract

The development of the ant communities and their foraging dynamics were studied in two annual agroecosystems of the Mexican tropical lowlands: a "forest milpa" of corn, beans, and squash made by cutting and buring 40-year-old forest, and a "field milpa" of corn, beans, and squash made by plowing 1-year-old second growth. The ant community was sampled using tuna fish baits 26, 52, 110 and 353 days after planting. Although immediately after planting the same number of ant species occurred in each milpa type, thereafter the ant faunas diverged. The field milpa became completely dominated by the native fire ant, Solenopsis geminata, while the number of ant species in the forest milpa gradually increased over time, reaching eight species 110 days after planting and 14 species by 353 days. Initially S. geminata dominated the ant fauna in the forest milpa (occurring on 90% of the baits), but by 353 days planting it was found on only 26% of the occupied baits. Ant foraging efficiency, as measured by proportion of tuna baits occupied and the removal rates of dead Drosophila fly baits, was much higher (by a factor of 2 to 3) in the field than the forest milpa. This was caused by the extremely high density of S. geminata colonies in the field milpa. The simple Solenopsis-dominated community of the field milpa may be much more effective in biological control than the more diverse community of the forest milpa. Although S. geminata has potential negative impacts in annual agroecosystems (it stings, eats corn seeds, and guards homopterams), its overall impact appears to be beneficial. As forested areas of the lowland wet tropics are increasingly cut and converted to annual agriculture, the primary ant inhabitant of these highly disturbed environments, S. geminata, will necessarily play a much more significant ecological role in agroecosystems.

Efecto del uso de suelo en las hormigas (Formicidae: Hymenoptera) de Tikinmul, Campeche, México

“…De acuerdo a estos patrones, donde se presenta una dominancia del género Pheidole, también existe una alta representatividad de otros géneros de las subfamilias Mymicinae, de las Ponerinae y Pseudomyrmecinae y en contraste una baja presencia de los géneros de las subfamilias Formicinae y Ecitoninae; mientras para la subfamilia Dolichoderinae, los patrones son difusos, ya que aunque no es frecuente un desplazamiento al encontrarse presentes especies de Pheidole, eventualmente puede ocurrir (Fowler 1993, Lieberburg et al 1975. En cuanto al microclima muchas especies de hormigas tropicales han mostrado ser sensibles a factores ambientales que pueden incrementar el riesgo de desecación, como la insolación y la baja humedad (Lighton & Feener 1989, Kaspari & Weiser 2000, aunque también existen especies que presentan predilección por los hábitats abiertos y expuestos al sol (MacGown & Lockley 2009, Risch & Carroll 1982, Torres-Contreras & Vásquez 2004. De acuerdo a sus preferencias las especies de hormigas pueden inclinarse por hábitats más abiertos como el monocultivo (i.e.…”

“…La mayor abundancia de S. geminata, que resalta en su dominancia en los monocultivos, se explica por su preferencia por áreas abiertas (Risch & Carroll 1982) e hidroquinesis negativa (Potts et al 1983, Cokendolpher & Francke 1985, dos condiciones similares a las encontradas en este sistema, donde los árboles están sembrados en espaciamientos de 3 × 4 m y la humedad relativa del suelo es baja. Sin embargo, esta especie no persiste si se da paso a la sucesión vegetal (Risch & Carroll 1982), posiblemente por el incremento de cobertura arbórea como consecuencia de este proceso.…”

“…Sin embargo, esta especie no persiste si se da paso a la sucesión vegetal (Risch & Carroll 1982), posiblemente por el incremento de cobertura arbórea como consecuencia de este proceso. Lo que podría explicar la menor abundancia de esta hormiga en los huertos caseros, donde la vegetación genera una mayor cobertura vegetal a lo largo del año.…”

Predacious activity of Ants (Hymenoptera: Formicidae) in conventional and in No-till agriculture systems

“…A large number of studies on the ant communities in the tropics were conducted in the natural ecosystems, although the evidence of similar ant functions in the agroecosystems can be found, particularly among the communities of the insects considered pests (Samways, 1983;Mansfield et al, 2003;Rossi and Fowler, 2004) or weeds (Risch and Carroll, 1982). The studies conducted in the Dourados region (MS, Brazil) showed the genera of Pheidole, Solenopsis, Dorymyrmex and Ectatomma as the insect predators in soybean (Fernandes et al, 1999).…”

Red imported fire ant invasion reduces the populations of two banana insect pests in South China

“…Ants are important predators in agroecosystems (Risch & Carroll, 1982;Way & Khoo, 1992) and have been used in pest management (Huang & Yang, 1987;Olotu et al, 2013), including the combination of ants in banana pest management programs banana (Sirjusingh et al, 1992;Gold et al, 2001). Our study provides evidence that S. invicta also can be an important biological control agent in banana plantation.…”