Thelazia callipaeda (Spirurida, Thelaziidae) eyeworm causes ocular infection in carnivores and humans in the Far East; this infection has been recently reported also in Europe--northern and southern Italy--in dogs, cats and foxes. The natural vector/s of T. callipaeda is/are unknown and the development of the nematode in its definitive hosts is limited to an experimental trial on dogs. To contribute new insights into the development of T. callipaeda in the definitive host in field conditions, eyeworms were collected from naturally infected dogs from an area with a high prevalence of infection (up to 60.14%) in the Basilicata region of southern Italy, from January 2002 to December 2003. Conjunctival secretions were also collected and examined for the presence of immature stages. The presence of blastomerized eggs throughout the period--except for the months from May to November--indicates a seasonality in the reproductive activity of T. callipaeda, coinciding with the presence/absence of the vector. In fact, 1st-stage larvae were found in the lachrymal secretions of dogs in summer (June--July 2002 and 2003), ready to be ingested by flies feeding about the eyes. The evidence of 4th-stage larvae in March 2002 and April, July and October 2003 may be accounted for by the presence of flies that act as intermediate hosts of T. callipaeda from early spring to early autumn. The presence of immature stages in October indicates an overlapping generation of nematodes and a 2nd cycle of vector infection. This basic knowledge of the development of T. callipaeda will hopefully help future epidemiological studies to identify the intermediate hosts and define the likely risk for vectors in field conditions.

1. The American bullfrog, Lithobates catesbeianus (Shaw, 1802), is considered one of the world's worst invaders because of its potential to affect native fauna adversely, especially amphibians, through predation, competition, breeding interference, and disease transmission.2. Here, the potential impact of introduced American bullfrogs (juveniles and adults) on native adult green frogs, Pelophylax kl. esculentus (Linnaeus, 1758), was investigated in a pond ecosystem by means of stomach-content and stable-isotope analyses. Specifically, this study was aimed at assessing the impact of the American bullfrog on native green frogs in terms of predation and competition (i.e. feeding ecology and habitat use), and uncovering changes in interspecific interactions linked to the ontogenetic dietary-habitat shifts of the invaders. 3. Stomach contents and isotope analyses suggest that L. catesbeianus changes trophic position in the food chain and undergoes ontogenetic dietary-habitat shifts during its life cycle. The species therefore has the potential to exert a double impact on native green frogs: as a predator at the adult stage and as a competitor (for food and habitat use) at the juvenile stage. 4. Stomach-content and isotope analyses gave similar results, suggesting that the predation impact by adult American bullfrogs on green frogs is mediated by the presence of the alien red swamp crayfish, Procambarus clarkii (Girard, 1852). Juvenile American bullfrogs and native amphibians overlap in their diet composition and in their habitat use, suggesting the existence of potential competition between the two species. 5. Ontogenetic dietary-habitat shifts in the American bullfrog, local conditions, and trophic interactions should be seriously considered in management approaches to promote the long-term coexistence of L. catesbeianus and native amphibians. Such management options have been neglected in the literature, and are worthy of further investigation to understand their efficacy on native species.

-This investigation was carried out in an area covering part of three southern Italian regions: Campania, Basilicata and Apulia. Eighty-one farms were involved using the formula suggested by Thrusfield; they were equally distributed over the area which was subdivided into 81 georeferenced sub-areas. In May and June 1999 from a total of 506 cattle, older than 18 months, blood-samples were taken and ticks were collected and identified. Serum samples were tested for antibodies of Babesia bigemina, Babesia bovis and Anaplasma marginale with an ELISA technique. Eight farms (9.8%) out of the 81 examined were positive for B. bigemina only, 3 (3.7%) for A. marginale only, and 70 (86.4%) for both. None of the animals of any farm was found to be positive for B. bovis. Out of the 506 sera tested, 117 (23.1 %) were positive for B. bigemina only, 58 (11.5%) for A. marginale only and 250 (49.4%) for both species; 81 (16.0%) were negative for all of them. Ticks were collected on animals on 62 (76.5%) out of the 81 farms. Adult ticks (1 410) were collected and identified; the highest number belonged to the Rhipicephalus bursa species (65.5%), followed by Rhipicephalus turanicus (8.6) and Haemaphysalis punctata (8.4). The results showed that B. bigemina, A. marginale and their potential vectors are common in the area examined and indicated that there is a risk for animals imported from tick-borne disease-free areas.

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Biological invasion studies have focused mostly on the competition and predation impact of invaders on native species; however, introduced species frequently interact with each other and, contrary to the ‘invasional meltdown theory’, such interactions may have non‐interactive effects on native fauna. Here, the effects of the interaction between American bullfrogs (Lithobates catesbeianus) and decapod crayfish on native amphibians have been investigated. Introduced American bullfrog populations were studied at two sites in central Italy (Rome, Latium), with their selection based on the presence or absence of the alien Procambarus clarkii. The pattern emerging from the fieldwork was then verified by a worldwide literature review on the trophic niche of the American bullfrog. Both field surveys and global diet analysis showed that the abundance of native amphibians in the American bullfrog diet was reduced when introduced crayfish occurred in both native and non‐native ranges. Thus, an alternative invasion model can be proposed in which the occurrence of one invader (P. clarkii) may reduce the negative effect of an alien predator (L. catesbeianus) on native species. The present findings suggest that the removal of invaders may not always be the best solution for protecting native prey, especially when alien species are interspersed with other introduced species. In such cases, multispecies operations, sequenced appropriately or undertaken simultaneously, would be preferable. Moreover, the identification of mechanisms facilitating the coexistence of native species with invaders can offer important management options.