Two new species of Archaeopodagrion (Odonata, Philogeniidae) from the western foothills of the Tropical Andes, with biological observations and distributional records

Two new species of the damselfly genus Archaeopodagrion, A. recurvatum sp. nov. and A. mayi sp. nov., are described from the confluence of the Tropical Andes and the Tumbes-Chocó-Magdalena biodiversity hotspots. Adults differ from the other known species in the shape of female posterior lobe of pronotum and male structures of cerci and paraprocts; the larva differs from other Archaeopodagrion species in the caudal lamellae structure and in the mandibular formula. The two new species are diagnosed, a morphological key to all known males and females in the genus is provided, and geographical distributions are updated. Finally, observations on habitat preferences for each newly described species are provided.

The larva and female ofPerigomphus basicornisAmaya-Vallejo, Novelo-Gutiérrez & Realpe, 2017, and the first record ofPerigomphus pallidistylus(Belle, 1972) for Colombia (Insecta: Odonata: Gomphidae)

The larva and female of Perigomphus basicornis are described and illustrated, and compared with the larva and female of P. pallidistylus. The larva of P. basicornis differs from that of P. pallidistylus in having sternum 8 divided in five sclerites, abdominal segments 8 and 9 with small, low protuberances on the tergites and male’s epiproct as long as its basal width, mainly. The female of P. basicornis differs from that of P. pallidistylus in having the apical lobes of vulvar lamina wider, with divergent tips. P. pallidistylus is recorded for Colombia for the first time.

The genus <i>Heteragrion</i> (Odonata: Zygoptera) in Northwestern Colombia, with the description of <i>Heteragrion</i> <i>tatama</i> sp. nov

The Neotropical forest specialist genus Heteragrion counts with 54 species and one subspecies described to date, eight of which have been recorded from Colombia. Here, information on Heteragrion species resulting from ten years of exploration of northwestern Colombia and examination of museum collections, including types and species from Central America, is presented. A new species endemic to the Tatamá National Park in the western Andes, Heteragrion tatama sp. nov. is described, as well as the female of Heteragrion aequatoriale Selys, 1886. Heteragrion calendulum Williamson, 1919 was rediscovered, a century after its first collection, which allowed us to compare it with Heteragrion atrolineatum Donnelly, 1992, and to conclude that the latter species is its junior synonym. We present pictures of female prothoracic intersternite, which offer valuable taxonomic information. The variation in coloration patterns for H. aequatoriale and Heteragrion mitratum Williamson, 1919 is discussed, and maps with new distributional data, a taxonomic key, natural history notes and photographs of the Heteragrion species distributed west of the Magdalena valley in Colombia, are also provided.

The larvae of Epigomphus jannyae Belle, 1993 and E. tumefactus Calvert, 1903 (Insecta: Odonata: Gomphidae)

The taxonomic knowledge about immature stages of the insect order Odonata (dragonflies and damselflies) is rather limited in tropical America. Here, the larvae of Epigomphus jannyae Belle, 1993 and E. tumefactus Calvert, 1903 are described, figured, and compared with other described congeners. E. jannyae larva is characterized by 3rd antennomere 1.6 times longer than its widest part; ligula very poorly developed, with ten short, truncate teeth on middle; apical lobe of labial palp rounded and smooth. Lateral margins on abdominal segments (S5–9) serrated, lateral spines on S6–9 small and divergent; male epiproct with a pair of dorsal tubercles at basal 0.66; tips of cerci and paraprocts strongly divergent. The larva of E. tumefactus is characterized by 3rd antennomere 2.3 times longer than its widest part, ligula with 6–7 truncate teeth, apical lobe of labial palp acute and finely serrate. Lateral margins of S6–9 serrate, lateral spines on S7–9; male epiproct with a pair of dorsal tubercles at basal 0.50. Differences with other species were found in 3rd antennomere, lateral spines of S7–9, and the caudal appendages. Epigomphus larvae inhabit small, shallow creeks (1st order streams) where they live in fine benthic sediments. When mature, the larva leaves the water in shady places, climbing small rocks at the water’s edge and metamorphosing horizontally on flat rocks. These new descriptions bring the total number of Epigomphus species with known larval stages to eight; only 28% of the species in this genus are known as larva.

The Ambrysus Stål (Heteroptera: Naucoridae: Cryphocricinae) of Mexico: <br />Revision of the subgenus Syncollus La Rivers

The subgenus Ambrysus (Syncollus) La Rivers is mostly Neotropical and includes nine described species. Features uniting species in this subgenus are related to the position of the propleura with respect to the prosternum in males and females, as well as characteristics of tergum V and the genitalia of males. Three species of Syncollus are known from Mexico including Ambrysus baeus Polhemus & Polhemus, A. circumcinctus Montandon, and A. pygmaeus La Rivers. The remaining six species in the subgenus are distributed in Central and South America. Herein we review Syncollus and revise the Mexican fauna. More specifically, three new species from Mexico are described: A. chiapanecus n. sp., A. totonacus n. sp., and A. xico n. sp. The subspecies A. circumcinctus caliginosus Usinger, A. c. concavus La Rivers, and A. c. extremus La Rivers are proposed as junior synonyms of A. c. circumcinctus Montandon. Ambrysus partridgei De Carlo is transferred from Syncollus to the subgenus Ambrysus.

Un caso de éxito en la restauración de un humedal tropical mediante la evaluación del ensamble de larvas de Odonata (Insecta)

<strong>Abstract. A case of successful restoration of a tropical wetland evaluated through its Odonata (Insecta) larval assemblage. </strong>This article provides numerical study of the Odonata larvae from a tropical recovered wetland located in La Mancha (LM, Ramsar site 1336), Veracruz, Mexico. Larval surveys were performed during the dry and rainy seasons of 2010 and 2011 and compared to a reference site in the locality of Cansaburro (CB). The effect of site, season and year on Odonata larval abundance was explored and diversity, richness, evenness and abundance distributions of both assemblages were compared. A total of 3,718 larvae from 25 species (five Zygoptera and 20 Anisoptera) in 14 genera and three families were collected from both wetlands. Species number was equal to both wetlands although abundance was significantly higher in LM. Diversity and species abundance patterns in both sites were similar although Shannon diversity was significant and slightly higher in the reference site. Differences in species composition and species dominance order between both assemblages were observed and addressed to differences in the aquatic plant structure between both wetlands which is mainly affected by management in La Mancha and by cattle grazing in Cansaburro. While the diversity of La Mancha was lesser than the reference site, most of the results of this investigation showed that La Mancha wetland has been successfully recovered.

Description of the larva of Epigomphus crepidus Kennedy, 1936 (Odonata: Gomphidae)

The larva of Epigomphus crepidus Kennedy is described and figured and compared with other described congeners. It is characterized by 3rd antennomere spindle-shaped, flattened dorso-ventrally, twice longer than its widest part; ventral pad of hypopharynx pentagonal; prementum subrectangular, with lateral margins slightly convex on apical 0.60; ligula very poorly developed, with a ventral row of nine short, truncate teeth on middle, and dorsal rows of short, stout piliform setae. Abdomen lacking dorsal protuberances, lateral spines on S7-9 divergent; sternites 3-8 divided into five plates, sternites 2 and 9 divided into three plates; male epiproct with a pair of dorsal tubercles rounded apically and divergent at basal 0.30. It differs from other species mainly in 3rd antennomere, sides of prementum and serrations on lateral margins of S7-9.

[Leaf litter decomposition in six Cloud Forest streams of the upper La Antigua watershed, Veracruz, Mexico]

Leaf litter decomposition is an important stream ecosystem process. To understand factors controlling leaf decomposition in cloud forest in Mexico, we incubated leaf packs in different streams along a land use cover gradient for 35 days during the dry and wet seasons. We assessed relations between leaf decomposition rates (k), stream physicochemistry, and macroinvertebrates colonizing leaf packs. Physicochemical parameters showed a clear seasonal difference at all study streams. Leaves were colonized by collector-gatherer insects, followed by shredders. Assessment of factors related to k indicated that only forest cover was negatively related to leaf decomposition rates. Thus stream physicochemistry and seasonality had no impact on decomposition rates. We concluded that leaf litter decomposition at our study streams is a stable process over the year. However, it is possible that this stability is the result of factors regulating decomposition during the different seasons and streams.

[Generic diversity of Trichoptera (Insecta) of Paramo Rabanal (Cundinamarca-Boyacá, Colombia)]

Trichopterans are considered an important and diverse biotic element in continental aquatic ecosystems. The purpose of this study was to evaluate the assemblages of the order Trichoptera in two subwatersheds with a gradient of disturbance. Four sampling events were conducted in two subwatersheds in the Eastern Mountain Range of the Colombian Andes. For the analysis we used rarefaction curves, Bray-Curtis Index and Partitioning Diversity and total richness and Shannon's diversity as metrics. Although total richness was similar between both subwatersheds, abundance was always highest in streams within the conserved subwatershed. Each subwatershed was dominated by different genera, except Ochrotrichia, which was abundant at all sites. Alpha diversity was similar among streams in the conserved watershed, while a reduction in diversity potentially associated with the disturbance gradient was observed in streams of the disturbed subwatershed. Beta diversity (0Dbeta and 1Dbeta) between subwatersheds and among conserved streams was similar, while in disturbed streams a similar gradient to that of alpha diversity was found. The similitude analysis clustered streams according to their conservation status. Differences found in trichopteran assemblages do confirm that the use of their attributes is adequate to assess the conservation status of stream ecosystems. Rev. Biol. Trop. 62 (Suppl. 2): 97-110. Epub 2014 April 01.

Efficacy and non-target impact of spinosad, Bti and temephos larvicides for control of Anopheles spp. in an endemic malaria region of southern Mexico

Background

The larvicidal efficacy of the naturally derived insecticide spinosad, for control of immature stages of Anopheles albimanus and associated culicids, was compared to that of synthetic and biological larvicides. Effects on non-target insects were also determined.

Methods

A field trial was performed in replicated temporary pools during the rainy season, in southern Mexico. Pools were treated with 10 ppm a.i. spinosad (Tracer 480SC), Bti granules applied at 2 kg/ha (VectoBac WDG, ABG-6511), and 100 ml/ha temephos (50 EC), or an untreated control. Numbers of immature mosquitoes, and aquatic insects in pools were monitored for 20 weeks.

Results

Samples of immature mosquitoes comprised approximately 10% An. albimanus, 70% Culex spp. (mostly Cx. melanoconion and Cx. coronator) and 20% Uranotaenia lowii. The most effective larvicides were spinosad and temephos that eliminated An. albimanus in 16 out of 20 post-treatment samples, or 9 weeks of continuous control of immature stages, respectively. These larvicides resulted in 15 and 5 weeks of elimination of Culex spp., respectively, or 20 and 4 weeks of continuous elimination of U. lowii, respectively. Bti treatment provided little consistent control. Aquatic insects were recorded comprising 3 orders, 20 families, 40 genera and 44 species. Shannon diversity index values (H’) for aquatic insects were highest in the control (0.997) and Bti (0.974) treatments, intermediate in the spinosad treatment (0.638) and lowest in the temephos treatment (0.520). Severely affected non-target insects in the spinosad and temephos treated pools were predatory Coleoptera, Hemiptera and Odonata, which in the case of spinosad was likely due to the high concentration applied. Bti had little effect on aquatic insects.

Conclusions

The spinosad treatment retained larvicidal activity for markedly longer than expected. Spinosad is likely to be an effective tool for control of anopheline and other pool-breeding mosquitoes in tropical regions. Non-target effects of spinosad on aquatic insects merit further study, but were likely related to the concentration of the product used.

Diversity of mosquitoes and the aquatic insects associated with their oviposition sites along the Pacific coast of Mexico

BACKGROUND

The abundance, richness and diversity of mosquitoes and aquatic insects associated with their oviposition sites were surveyed along eight states of the Pacific coast of Mexico. Diversity was estimated using the Shannon index (H'), similarity measures and cluster analysis.

METHODS

Oviposition sites were sampled during 2-3 months per year, over a three year period. Field collected larvae and pupae were reared and identified to species following adult emergence. Aquatic insects present at oviposition sites were also collected, counted and identified to species or genus.

RESULTS

In total, 15 genera and 74 species of mosquitoes were identified: Anopheles pseudopunctipennis, An. albimanus and Aedes aegypti were the most abundant and widely-distributed species, representing 47% of total mosquito individuals sampled. New species records for certain states are reported. Anopheline diversity was lowest in Sinaloa state (H' = 0.54) and highest in Chiapas (H' = 1.61) and Michoacán (H' = 1.56), whereas culicid diversity was lowest in Michoacán (H' = 1.93), Colima (H' = 1.95), Sinaloa (H' = 1.99) and Jalisco (H' = 2.01) and highest in Chiapas (H' = 2.66). In total, 10 orders, 57 families, 166 genera and 247 species of aquatic insects were identified in samples. Aquatic insect diversity was highest in Chiapas, Oaxaca and Michoacán (H' = 3.60-3.75). Mosquito larval/pupal abundance was not correlated with that of predatory Coleoptera and Hemiptera.

CONCLUSION

This represents the first update on the diversity and geographic distribution of the mosquitoes and aquatic insects of Mexico in over five decades. This information has been cataloged in Mexico's National Biodiversity Information System (SNIB-CONABIO) for public inspection.

Description of the larva of Argia chelata Calvert, 1902 (Odonata: Coenagrionidae)

The larva of Argia chelata is described and figured. It falls into the group of Argia larvae with a moderately prominent ligula and two palpal seta, but it differs from its closest relatives by having labial palp with 2 setae plus one basal setella; the length of the ligula is 30% of its maximum width; basal tergites (1-5) lacking long, fine setae, mainly on midline; S8-10 mostly dark brown; paraprocts with spiniform setae on basal 0.25 and 0.55 of dorsal and ventral borders, respectively. Larvae were found in 2^nd to 4^th order shallow streams in cloud forest, crawling among debris, fine sand and mud where the water flow is slow or still, close to the shoreline. The larva is compared with A. lacrimans (Hagen), A. pima Garrison, and A. tonto Calvert, species apparently closely related. 

Two new species of Psephenops Grouvelle from Belize (Coleoptera: Byrrhoidea: Psephenidae), with a key to the known species from Mexico and Central America

Two new species, Psephenops spiniparameri sp. nov. and P. shepardi sp. nov. are described, based on specimens collected from Cayo and Toledo Districts in Belize, bringing the total number of described species assigned to the genus to ten.

Diversity and distribution of Odonata (Insecta) larvae along an altitudinal gradient in Coalcomán mountains, Michoacán, Mexico

Evaluating components of landscape diversity is essential for the implementation of efficient conservation strategies. We evaluated the diversity of Odonata larval assemblages from the Coalcomán mountains (CM), Michoacán, Mexico, and related it to local (site-level) habitat variables. Larvae were collected from shores, riffles and pools in five streams, counted and identified to species, twice per season during 2005. The Shannon Diversity Index (H'), Margalef's Richness Index (R), Simpson's Index as a dominance measure (D) and Pielou's Equitability (J) were used to describe the assemblages, and Renyi's Diversity Profiles were used to order diversity. A Bray-Curtis Similarity Index (BC) was used to evaluate beta diversity. Theoretical richness was estimated using non-parametric and parametric methods. A Canonical Correspondence Analysis (CCA) was applied to explore the relationships of species with site-level environmental variables. A total of 12 245 larvae from 75 species, 28 genera and 8 families were recorded. Over all sites, the dominant species were Erpetogomphus elaps, Macrothemis pseudimitans and Argia pulla. The number of species per locality ranged from 18 to 36, and a high number of species (76%) occurred with relative abundances lower than 1%. A differential distribution of species and abundance in streams, time and strata was observed. Renyi's diversity profiles showed diversity was higher in spring and on shores. Most BC similarity values were smaller than 25%, indicating a high turnover rate in the CM. The high turnover rate reflects a differential distribution of the species along the altitudinal gradient, supporting the hypothesis of Mexico as a betadiverse country. According to the slope of Clench's curve, a reliable list of species was gathered. The CM larval assemblage is currently the largest reported for Mexico, and our results support previous proposals of the CM as a species-rich area for conservation.

Spinosad toxicity to Simulium spp. larvae and associated aquatic biota in a coffee-growing region of Veracruz State, Mexico

Spinosad is a naturally derived insecticide that has shown potential as a mosquito larvicide. To determine the activity of spinosad against blackflies, late-instar larvae from a community comprising Simulium triittatum (63.6%) and seven other species, including three known vectors of onchocerciasis in Mexico (S. metallicum, S. ochraceum, and S. callidum), were subjected to concentration-mortality laboratory bioassays following World Health Organization guidelines. Cephalic capsule measurements confirmed the relatively homogeneous distribution of experimental larvae. The 50% lethal concentration of spinosad was estimated at 1.48 ppm spinosad (95% confidence interval: 1.07-2.33) for a 10-min exposure period, whereas larvae treated with 0.05 ppm of the organophosphate temephos experienced 61% mortality. Immature aquatic insects were identified to genus and tested for their susceptibility to spinosad in the laboratory. After exposure to 12 ppm spinosad for 10 min, ephemeropterans, odonates, trichopterans, and hemipterans did not experience significantly increased mortality over that of untreated controls, whereas a significant increase in mortality was observed in spinosad-treated Plecoptera (P < 0.001). Tilapia and trout fry exposed to 12 ppm spinosad for 10 min did not experience increased mortality at 24-h postexposure over that of the controls. We conclude that spinosad is less toxic than temephos to these blackfly species, but is likely to have a low impact on nontarget members of the aquatic community.