Hugo Delfin - Academia.edu (original) (raw)

Papers by Hugo Delfin

Florida Entomologist, 2002

Medical and Veterinary Entomology, 1998

The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F... more The effect of the introduction of the entomophagous copepod Mesocyclops longisetus (Acuacultura F.C.B. strain) on the survival of Aedes aegypti immature stages in car tyres was evaluated under semi-natural conditions in the municipality of Merida, Yucatan, Mexico. Life tables were constructed for the immature stages of the mosquito in the presence and absence of M. longisetus, and the survival data were compared using log-linear models. The data set was adjusted using the GLIM statistical package and the quality of adjustment was evaluated with a chi-squared test. Survivorship curves were constructed for each treatment.

Neotropical Entomology, 2009

New distribution records of 22 braconid species belonging to Agathidinae, Braconinae, Helconinae,... more New distribution records of 22 braconid species belonging to Agathidinae, Braconinae, Helconinae, Homolobinae and Rogadinae subfamilies from Brazil, Chile, Costa Rica, Guatemala, Mexico and Panama are presented. Agathirsia ninesevenci Pucci & Sharkey is reported for the first time from Mexico; Homolobus acares van Achterberg, H. antefurcalis van Achterberg and H.infumator (Lyle) from Costa Rica; Triaspis kurtogaster Martin from Brazil, Costa Rica and Panama. Sabulodes caberata Guenée (Lepidoptera: Geometridae) is recorded as a new host for Homolobus infumator (Lyle).

The role of flies, particularly Musca domestica, in the transmission of diarrhoeal diseases is no... more The role of flies, particularly Musca domestica, in the transmission of diarrhoeal diseases is not clear even though there is evidence that they are carriers of a wide range of humans pathogens. The present review summarises the information produced during the last 50 years in relation to the potential mechanisms of transmission, main pathogens isolated from flies, a discussion of the evidence incriminating these insects, important features of the different control mechanisms implemented and the antecedents of these topics in Mexico.

Environmental Entomology, 2006

Ichneumonoidea is an important group in terrestrial ecosystems, although its community structure ... more Ichneumonoidea is an important group in terrestrial ecosystems, although its community structure in tropical agricultural environments is unknown. Consequently, a characterization of ichneumonoid communities was done in an agricultural environment consisting of a cultivated area with and without surrounding vegetation in the state of Yucatan, Mexico. The characterization helped to understand how Ichneumonoidea diversity changes in the vegetation structure adjacent a crop. Three sampling sites were established: nine experimental plots in open area with continual agricultural use without surrounding vegetation (NSV), nine experimental plots with surrounding vegetation in a remaining patch (WSV), and nine plots inside of secondary vegetation of a remaining 7-yr-old patch (SV). Ichneumonoidea specimens were collected with Malaise and yellow pan traps. A total of 1,715 specimens were collected, divided into 40 subfamilies, resulting in 138 genera and 480 species. Of these, Braconidae accounted for 1,115 specimens from 21 subfamilies, 84 genera, and 342 species, whereas Ichneumonidae was represented by 600 individuals from 19 subfamilies with 54 genera and 142 species. Braconidae had higher species richness, abundance, and diversity than Ichneumonidae. Both families exhibited higher diversity in the treatment with surrounding vegetation. Koinobiont species were most common in both families. We suggest that vegetation structure and spatial distribution seem to have greater effect on community structure. Our results suggest that Ichneumonoidea could be a better indicator of the degree of disturbance than of environmental preservation.

Scarabaeinae are sensitive to structural habitat changes caused by disturbance. We compared copro... more Scarabaeinae are sensitive to structural habitat changes caused by disturbance. We compared copronecrophagous beetle (Scarabaeinae) community structure in three differently managed zones within an agroecosystem of the northern Yucatan Peninsula, Mexico. We placed dung and carrion traps once a month from June 2004 through May 2005. The beetle community included 17 species from the genera Canthon, Canthidium, Deltochilum, Pseudocanthon, Malagoniella, Onthophagus, Phanaeus, Copris, Uroxys, Sisyphus and Ateuchus. The secondary vegetation had a higher beetle diversity than the other two zones. Species richness was highest in the Brosimum alicastrum plantation. The pasture had the lowest species diversity and richness, but exhibited the highest abundance of Scarabaeinae in the dry season. The two zones with extensive tree cover were the most diverse. Roller beetles were dominant over burrower species and small-sized species outnumbered large species. Our data show two important issues: beetle species in the pasture extended their activity to the beginning of the dry season, while abundances dropped in the other, unirrigated zones; and the possibility that the Scarabaeinae living in neotropical forests are opportunistic saprophages and have specialized habits for resources other than dung. The B. alicastrum plantation is beneficial to the entire ranch production system because it functions as a dispersion and development area for stenotopic species limited to tree cover. Rev. Biol. Trop. 55 (1): 83-99. Epub 2007 March. 31.

Neotropical Entomology, 2007

Beetles were collected from April 2002 to July 2003 from the following sites in the centre of the... more Beetles were collected from April 2002 to July 2003 from the following sites in the centre of the state of Veracruz located every 200 m along an altitudinal gradient (1000 1400 m asl): three fragments of cloud forest, three shaded coffee plantations, an open canopy coffee plantation, secondary forest, and a pasture. A total of 9,982 specimens were captured, belonging to the families Scarabaeidae and Trogidae, and representing 21 genera and 50 species. The genera Ataenius Harold, Onthophagus Latreille and Aphodius Illiger represented 48% of the species of Scarabaeidae. Species richness was found to decrease with increasing altitude; there were 36 species at 1000 m asl, 27 species between 1200 and 1300 m asl, and 26 species at 1400 m asl. Abundance along the altitudinal gradient follows a pattern of few abundant species and many species with few specimens. Beetle activity is related to precipitation. In the nine communities studied, species richness was observed to increase when precipitation was greater than 100 mm at the beginning of the rainy season. On the landscape scale, there were 44 species during the rainy season, 22 during the windy nortes season, and 24 during the dry season. In terms of trophic guild, 40% of the beetles captured were saprophagous that feed on decomposing organic material from plants and 60% were saprophagous that feed on decomposing organic material from animals (30% necrophagous, 26% coprophagous, 4% telio-necrophagous).

Florida Entomologist, 2006

In order to carry on the detection and species inventory of hymenopteran parasitoids associated w... more In order to carry on the detection and species inventory of hymenopteran parasitoids associated with fruit flies, we examined various tropical fruits growing at the Southern region of Yucatan. During a yearly cycle (Jun 2000 to Jun 2001), 9 host fruit species (including some varieties) were collected by 2 different methods. The first method involved weekly collection of ripened fruits that were transported to the laboratory ("Fruit-Lab"); and the second method was collection of fruits placed on the ground below the tree canopy ("Fruit-Beds"), and which remained in the field for two weeks, after which they were transported to the laboratory. Fruits obtained were counted and weighed, and the recovered pupae were quantified for each sample. As a whole, we sampled 4,470 fruits (850.8 Kg) from the 9 host plant species and varieties, which were infested by 5 fruit fly species: Anastrepha ludens (Loew), A. obliqua (Macquart), A. serpentina (Wiedemann), A. striata Schiner, and A. fraterculus (Wiedemann). The average parasitism in all samples was 3.69% represented by 11 hymenopteran species as follows: Braconidae, Doryctobracon areolatus (Szépligeti), and Opius bellus (Gahan); Figitidae, Aganaspis pelleranoi (Brethes), Aganaspis sp., Odontosema anastrephae Borgmeier and Odontosema sp.; Diapriidae, Coptera haywardi (Oglobin); Chalcididae, Dirhinus sp.; Pteromalidae, Spalangia endius Walker; Eurytomidae, Sycophila sp.; and Perilampidae, Euperilampus sp. On the basis of results in differences among samples for parasitism rates, fruit fly parasitoid, and fruit fly host plant, parasitoid assemblages are analyzed and discussed.

Florida Entomologist, 2007

Biotropica, 2010

Spatial variation in the strength of herbivore top-down control represents an important source of... more Spatial variation in the strength of herbivore top-down control represents an important source of variation in plant fitness measures and community structure and function. By measuring seed predator (larvae of a Noctuid moth) and parasitoid impacts on Ruellia nudiflora across a broad spatial scale in Yucatan (Mexico), this study addressed the following: (1) to what extent does seed predator and parasitoid attack intensity associated with R. nudiflora vary spatially? (2) Does parasitoid attack result in a positive indirect effect on the plant, and does the intensity of this effect vary spatially? During the peak of fruit production (late June–early July) of 2005, we collected fruits from 21 R. nudiflora populations and grouped them into four regions: center, east, north and south. For each fruit we recorded: observed seed number, number of seeds eaten, seed predator presence, parasitoid presence and number of seeds ‘saved’ by parasitoids. Seed predators attacked ca 30 percent of fruits/plant on average, while parasitoids were found in 24 percent of seed predator-attacked fruits. Results indicated spatial variation in seed predator and parasitoid attack levels; interestingly, a contrasting spatial gradient of attack intensity was observed: populations/regions with greatest parasitoid attack levels usually had the lowest seed predator attack levels and vice versa, suggesting top-down control of parasitoids on seed predators. We observed a weak overall indirect impact of parasitoids on R. nudiflora (4% seeds ‘saved’ on average), which nonetheless varied strongly across populations (e.g., close to 14% seeds saved at one population). Findings indicate a geographical structuring of interaction strengths across populations, as well as spatial variation in the strength of parasitoid cascading effects on plant reproduction.El presente estudio es un esfuerzo por cuantificar la intensidad de efectos de un depredador de semillas (DS) y sus parasitoides sobre la hierba Ruellia nudiflora a una escala espacial amplia en Yucatán (México). Los objetivos fueron: (1) Determinar si existe variación espacial en la intensidad de efecto del DS y los parasitoides sobre R. nudiflora, y (2) Determinar si existe un efecto indirecto positivo de los parasitoides sobre R. nudiflora, y si la intensidad de este efecto varía espacialmente. De finales de junio a principios de julio del 2005 se realizó una colecta de frutos de 21 poblaciones de R. nudiflora agrupadas en cuatro regiones (norte, centro, este, sur). Para cada fruto se registró: número observado de semillas, número de semillas depredadas, presencia del DS y/o el parasitoide, y número de semillas salvadas por parasitoides. El DS atacó en promedio el 30% de los frutos por planta, mientras que los parasitoides estuvieron presentes en el 24% de los frutos atacados por el DS. Se observó un alto nivel de variación espacial en los niveles de ataque por el segundo y tercer nivel trófico; sin embargo, la intensidad de ataque de cada uno se ordenó espacialmente de manera opuesta: las poblaciones/regiones con mayor incidencia del parasitoide fueron generalmente las menos atacadas por el DS y viceversa (sugiriendo un control de los parasitoides sobre el herbívoro). Aunque en general se observó un efecto indirecto débil de los parasitoides sobre la planta (4% de las semillas producidas por planta fueron salvadas por parasitoides), éste varió fuertemente entre poblaciones (e.g., hasta 14% de semillas salvadas en una de las poblaciones). Los resultados indicaron una marcada estructuración espacial en la intensidad de las interacciones del sistema tritrófico bajo estudio, en particular del efecto de cascada trófica de los parasitoides sobre la planta.

Studies on Neotropical Fauna and Environment, 2011

Exasticolus xmatkuilensis sp. n. (Hymenoptera: Braconidae: Homolobinae) is described from the Sta... more Exasticolus xmatkuilensis sp. n. (Hymenoptera: Braconidae: Homolobinae) is described from the State of Yucatan, Mexico. It is the first species of the genus known from the Yucatan Peninsula. A key to the species of the genus Exasticolus van Achterberg is added. Exasticolus rosenbergi (Viereck, 1911) is taken from the synonymy with E. fuscicornis (Cameron, 1887) and treated as a valid species.