|Smith, David R|
Submitted to: Veterinary and Human Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2000
Publication Date: N/A
Interpretive Summary: Larvae of a sawfly from southern Brazil and Uruguay moves and feeds on grasses and other debris in groups of up to 100 individuals. Larvae are toxic to pigs and other livestock and may cause their death if ingested. Studies have determined the chemicals involved in the toxicant and how much will cause sickness and death in pigs. Recognition of each stage of the sawfly is important to researchers and agricultural agents. The female, male, and larvae of this species are described and illustrated. Familiarity with the characters used to separate this species from other sawflies will prevent its confusion with non-toxic species and thus prevent costly control measures. This information will be useful to insect identifiers, researchers working on hogs, and insect taxonomists. APHIS identifiers will also be alerted so as to prevent introduction into the United States of this sawfly.
Technical Abstract: Two pigs were dosed with 5 and 10g/kg bw of fresh Perreyia flavipes larvae collected at the municipality of Pelotas. Two other pigs were dosed with 0.87 and 1.7g/kg of dry P. flavipes (equivalent to 5 and 10g/kg bw of fresh larvae). Another pig was dosed with 0.17g/kg of dry larvae, daily, during 20 d. Forty-eight hours after the ingestion, all pigs that ingested single edoes showed clinical signs and marked rise in serum aspartate aminotransferase. Alanine aminotransfersae and gamma glutamiltransferase were also slightly increased. The pig dosed with 10g/kg of fresh larvae dies in 96 hours. The others recovered in 4-5 d after ingestion. No clinical signs were observed in the pig dosed during 20 d with 0.17g/kg of dry larvae. The main lesion observed in the pig dosed with 10g/kg of fresh larvae was a centrilobular liver necrosis. These results confirmed previous reports on the spontaneous intoxication by P. flavipes in swine, demonstrated that the larvae maintain the toxicity after been frozen or dried, and suggest no cumulative effect in the larval toxicity. Larvae collected in the field were conditioned in boxes containing swards of native grasses and covered with gauze to prevent the escape of adults on emergence. Larvae pupated from August 11 to September 25. Emergence of adults occurred from February 10 to March 4. Adult females and males live only 18-36 h, respectively. Theeggs had an incubation period of 26-33 d. The larval period extends from March 1 to August 24.