EFFECTS OF PESTICIDES ON THE DEVELOPMENT OF OOCYTES AND SAC EGGS OF ALPAIDA VENILIAE (ARANEAE, ARANEIDAE)

BENAMÚ, M.; M. SCHNEIDER; N. SÁNCHEZ & A. GONZÁLEZ

Córdoba, Argenina

Congreso; XI Congreso Argentino de Ciencias Morfológicas; 2008

Sociedad Argentina de Ciencias Morfológicas

In Argentina, transgenic soybean resistant to glyphosate (RR) has greatly expanded in recent decades. This resulted in a significant increase in the use of broad-spectrum insecticides and herbicide glyphosate. However, the Integrated Pest Management (IPM) paradigm claims for the integration of natural enemies of pests, selective pesticides, and another cultural techniques. Broad-spectrum pesticides are very toxic for most natural enemies. Alpaida veniliae (Araneae, Araneidae) is a weaver spider, very abundant in soybean crops and feed on many pests. The sublethal effects of several pesticides (cypermethrin, endosulfan, spinosad, methoxyfenozide) and the herbicide glyphosate on the development of the oocytes, the sacs eggs and eggs were evaluated. Sublethal concentrations of these products were applied by ingestion through the prey Musca domestica, treated by immersion. The prey was provided for 4 consecutive days. After 21 days post-treatment females were mated, and the dissection of the ovaries was conducted 15 days post-copulation. There was an abnormal development of oocytes in cypermethrin, endosulfan, spinosad and glyphosate treatments compared to the control, with a smaller development and the presence of fat aggregates between and on them. As a result, construction of sacs eggs was also abnormal in these treatments. Some of the eggs were found in poor condition or dehydrated. Methoxyfenozide had no effect on the development of oocytes and sacs eggs. Preliminary results show a negative impact of sublethal concentrations of many insecticides, two of them belonging to conventional pesticides and the herbicide glyphosate on A. veniliae. This study shows that not only is important to assess mortality, but other aspects related to performance, such as fertility, which are directly linked to its effectiveness for pest control. These studies will be complemented by quantitative tests to measure the reduction in size and number of oocytes in order to measure the impact on the reproductive potential of this predator.Alpaida veniliae (Araneae, Araneidae) is a weaver spider, very abundant in soybean crops and feed on many pests. The sublethal effects of several pesticides (cypermethrin, endosulfan, spinosad, methoxyfenozide) and the herbicide glyphosate on the development of the oocytes, the sacs eggs and eggs were evaluated. Sublethal concentrations of these products were applied by ingestion through the prey Musca domestica, treated by immersion. The prey was provided for 4 consecutive days. After 21 days post-treatment females were mated, and the dissection of the ovaries was conducted 15 days post-copulation. There was an abnormal development of oocytes in cypermethrin, endosulfan, spinosad and glyphosate treatments compared to the control, with a smaller development and the presence of fat aggregates between and on them. As a result, construction of sacs eggs was also abnormal in these treatments. Some of the eggs were found in poor condition or dehydrated. Methoxyfenozide had no effect on the development of oocytes and sacs eggs. Preliminary results show a negative impact of sublethal concentrations of many insecticides, two of them belonging to conventional pesticides and the herbicide glyphosate on A. veniliae. This study shows that not only is important to assess mortality, but other aspects related to performance, such as fertility, which are directly linked to its effectiveness for pest control. These studies will be complemented by quantitative tests to measure the reduction in size and number of oocytes in order to measure the impact on the reproductive potential of this predator.