Infection of perennial ryegrass (Lolium perenne) by an endophyte fungus (Neotyphodium lolii) decreases the abundance and diversity of predators and parasitoids

ABSTRACT Perennial ryegrass is one of the most important food sources in animal production. However, several pests affect this crop, and one of the primary control strategies is the symbiotic relationships between ryegrass endophyte fungi. This fungus produces alkaloids that exhibit toxic activity against arthropods. Furthermore, the effect of fungi may extend to higher trophic levels, including predators (spiders and/or insects), decreasing their abundance and diversity. Given the importance of spiders and insects as predators, whether the symbiotic interaction between perennial ryegrass and endophyte fungus reduces the abundance and diversity of predators pose an important question. To address this question, natural enemies in perennial ryegrass were collected and analyzed over a year, and the percentage of endophyte fungus was evaluated by the presence of hyphae from two ryegrass cultivars, Jumbo (E-) and Alto AR1 (E+). We observed an 80% endophyte infection rate for (E+) and 0% for (E-). Moreover, 222 individual spiders corresponding to 10 families were identified in both perennial ryegrasses, including 209 individuals for (E-) and 13 for (E+). The most abundant spider family was Lycosidae, representing 71.17% of the total spiders. In addition, 65 insects were collected, corresponding to 6 families, with Carabidae being the most abundant. Furthermore, the Simpson index indicated the dominance of the family Lycosidae. Overall, spider and insect abundance and diversity were reduced in (E+), suggesting a negative effect of the endophyte on predator populations.

Dispositivos intrauterinos en atención primaria / Intrauterine contraceptive devices in primary care

Se estudia, en forma retrospectiva, la evolución de 383 mujeres usuarias de dispositivos intrauterinos controlados en el Hospital de Peñaflor. El grupo incluye 280 casadas (73,1%) y 103 solteras (26,9%). Las últimas eran principalmente de paridad baja y usuarias de Tcu. Las casadas eran predominantemente multíparas y usuarias de Lippes. Las complicaciones observadas en orden de frecuencia fueron: expulsiones, metrorragia, procesos inflamatorios pelvianos y dismenorrea, pero con tasas menores a las descritas por otros autores. Las expulsiones fueron más frecuentes en pacientes menores de 29 años y de baja paridad. No existió relación entre los meses de uso del dispositivo y la frecuencia de los procesos inflamatórios pelvianos. La eficacia de los dispositivos para evitar embarazos fue de 2 por 100 años-mujer, valor semejante al señalado por otros estudios. Sin embargo, no se demostró que los dispositivos inertes (Lippes) fueran menos eficientes que los medicamentados (Tcu)