Hugo Delfín-González

Mesocyclops longisetuseffects on survivorship ofAedes aegyptiimmature stages in car tyres

Abstract.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.

Fauna de Coleópteros Scarabaeidae Laparosticti y Trogidae (Coleoptera: Scarabaeoidea) asociados al Bosque Mesofilo de Montaña, cafetales bajo sombra y comunidades derivadas en el Centro de Veracruz, México

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).

Hymenopteran Parasitoids of Anastrepha Fruit Flies (Diptera: Tephritidae) Reared from Different Hosts in Yucatan, Mexico

Abstract 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.

Lethal and Sublethal Effects of Ivermectin on Onthophagus landolti (Coleoptera: Scarabaeidae)

ABSTRACT Previous work has documented toxic effects of ivermectin (IVM) on dung beetles from the Old World, but very little is known about this drugs effect on Neotropical dung beetles. Accordingly, we conducted a bioassay with dung spiked with IVM to assess its lethal and sublethal effects on the Neotropical dung beetle Onthophagus landolti Harold. The experimental design consisted of five treated groups G1, G2, G3, G4, and G5 receiving 0.001, 0.01, 0.1, 1.0, and 10 mg IVM/kg dung fresh weight, respectively, and two control groups (solvent control [CGA] and untreated control [CGU]). Adult survival and fecundity were measured throughout a 10-d period, and subsequent egg development and survival were monitored. Adult survival was only affected for treatment groups G4 and G5 groups (70 and 30%, respectively); groups G1, G2, G3 and both controls exhibited 100% survival. Fecundity was completely suppressed under treatment groups G4 and G5. Group G3 only had 1.7 and 2.1% brood mass production relative to CGA and CGU, respectively. Additionally, for groups G1 and G2 the proportion of adults emerging from brood masses was lower relative to CGA. Furthermore, development time for the second generation in groups G1 and G2 was 12.5% slower relative to control groups. Finally, dung removal by beetles from groups G3, G4, and G5 was significantly lower relative to control groups. In conclusion, toxic effects of IVM on O. landolti are associated mainly with reduced fecundity and lower dung-removal by adult beetles as well as reduced survival and slower development of offspring.

Dung beetle (Coleoptera: Scarabaeinae) diversity and seasonality in response to use of macrocyclic lactones at cattle ranches in the mexican neotropics

Dung beetles provide recognised environmental services in cattle production systems, but can be negatively affected by the pharmaceutical residues found in excreta, particularly macrocyclic lactones (ML). The diversity and seasonal abundance of dung beetle communities were measured using baited pitfall traps and compared at four cattle ranches in Yucatan, Mexico, to assess the possible effects of ML residues. Cattle parasite control was performed at two of these ranches using ML. A total of 93 274 dung beetles from 17 species were collected. The dominant species at all four ranches were Onthophagus landolti and Canthon indigaceus chevrolati. Compared to ranches where ML was not used, total abundance was higher but richness, evenness and diversity were lower at ranches where ML was used. Five other species were identified as potential indicator species for determining whether there was an effect of ML use at the studied ranches. Seasonal patterns differed between beetle communities: those found at non‐ML sites occurred in higher abundances in May and July, while those at ML sites had higher abundances in May and June. This was probably because herds on ML sites were treated with ML to control parasites in early July. The application of ML for controlling cattle parasites was shown to have a negative effect on the diversity and abundance of dung beetles. These results emphasise the need for timing ML use in order to mitigate the adverse impacts on these insects.

Braconid Wasps (Hymenoptera: Braconidae) of Northern Yucatan, Mexico: Subfamilies Agathidinae and Doryctinae (excluding Heterospilus Haliday)

Abstract The Braconidae fauna (Agathidinae and Doryctinae, excluding Heterospilus Haliday) of the Ria Lagartos Biosphere Reserve in Yucatan, Mexico are recorded. Eighty-three species and 29 genera were found; of these 62 species are new records for Mexico. The general distribution and flight period of the taxa collected are provided.

Ichneumonoidea (Hymenoptera) Community Diversity in an Agricultural Environment in the State of Yucatan, Mexico

Abstract 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.

FIRST REPORT OF ANASTREPHA COMPRESSA IN MEXICO AND NEW RECORDS FOR OTHER ANASTREPHA SPECIES IN THE YUCATAN PENINSULA (DIPTERA: TEPHRITIDAE)

Tephritid flies (Diptera: Tephritidae) are known as “true fruit flies” due to the close relationship between their immature stages and their wild and domesticated host plants. They are the most important dipteran pests of agriculture worldwide (Christenson & Foote 1960) and include 481 genera and 4352 species (Norrbom et al. 1998). Anastrepha is the most economically important and diverse genus of fruit flies in the Americas, with 197 species distributed throughout tropical and subtropical areas (Norrbom et al. 2000). To date, 32 species are known to occur in Mexico, and seven of them have been reported for the Yucatan Peninsula (YP). This includes the Mexican states of Campeche, Quintana Roo and Yucatan. Anastrepha species reported for each state are: Campeche ( Anastrepha fraterculus, A. hamata, A. limae, A. obliqua, A. serpentina ); Quintana Roo ( A. hamata, A. ludens, A. obliqua, A. serpentina ); and Yucatan ( A. fraterculus, A. ludens, A. serpentina, A. striata ) (Hernández-Ortiz 1992). This work provides new locality records for Anastrepha species already reported for YP, first records of three species in YP ( A. ampliata, A. pallens and A. spatulata), and the first record of A. compressa for Mexico. Material examined is deposited at the Colección de Insectos, Instituto de Ecología A.C. Xalapa, Veracruz (IEXA), and Colección Entomológica Regional of the Universidad Autónoma de Yucatán (CER).

New neotropical distribution records of braconid wasps (Hymenoptera: Braconidae)

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).

Life History of Onthophagus landolti Harold, 1880 (Coleoptera: Scarabaeidae), with Descriptions of the Preimaginal Stages

Abstract The life history and morphology of the third instar and pupa are described for Onthophagus landolti Harold, 1880 (Coleoptera: Scarabaeidae). Instar developmental time was determined by analyzing cephalic width data using generalized linear models. Morphological descriptions were done of the third instar and pupa, comparing taxonomically relevant characters to other species of Onthophagus Latreille, 1802 species. Developmental time took 30 days from egg to teneral imago. The egg period lasted 2–3 days, the larval period 20–22 days, and the pupa 6–8 days. Cephalic width ranged 0.750–0.850 mm for the first instar, 0.925–1.075 mm for the second instar, and 1.125–1.300 mm for the third instar. Duration of the first instar was 2–3 days, the second instar lasted 3 days, and the third instar 10–13 days. Onthophagus landolti larvae exhibit morphological characters common to other American Onthophagus. The principal interspecific variation in chaetotaxy was observed on the labium-hypopharynx.