Monika Springer

Life history of five small minnow mayflies (Ephemeroptera: Baetidae) in a small tropical stream on the Caribbean slope of Costa Rica

Life history characteristics of five species of Baetidae were investigated over a one-year period at Quebrada González, a warmwater stream in Braulio Carrillo National Park. Larvae of three species of Baetodes and two species of Camelobaetidius were collected at monthly intervals. Measurements of head capsules show a wide size range within each species throughout the year. For all species studied, mature larvae with black wings pads were found during all months. Fecundity averaged less than 1000 eggs per female for all species. The asynchronous development, multiple overlapping cohorts, and long emergence period with reproduction occurring throughout the year suggest a multivoltine life history for all five species. The high water temperatures (annual mean 21.4°C, ranging from 20.6°C to 22.1°C) throughout the year undoubtedly contribute to these life history patterns. The multivoltinism of these mayflies conforms to a general pattern of multivoltinism for aquatic insects in tropical regions.

First Description of the Larva of Pharceonus Spangler et Santiago-Fragoso, 1992, and New Records for the Genus (Coleoptera: Elmidae: Larainae)

The larva of the genus Pharceonus is described for the first time from material collected in Costa Rica and Peru. These are the most northern and southern distribution records for this genus, which was previously known from just one species, Pharceonus volcanus Spangler et Santiago-Fragoso 1992, from Panama.

The neotropical damselfly genus Cora: new larval descriptions and a comparative analysis of larvae of known species (Odonata: Polythoridae)

The final larval stadium of four species of Cora are described and compared with known species in the genus. Cora skinneri Calvert, 1907, C. semiopaca Selys, 1878 and C. lugubris Navás, 1934 are described and illustrated for the first time using material from Costa Rica for the first two and from Colombia for the latter. A redescription of C. marina Selys, 1868 from specimens collected in Costa Rica is also included for comparison. Although all species are very similar as larvae, two major groups can be differentiated based on the shape of the caudal gills. The three species here described for the first time are very similar, but can be separated from each other using a combination of characters. Se describen los estadios finales de las larvas de tres especies de Cora y se comparan con las especies conocidas en el género. Cora skinneri Calvert, 1907, C. semiopaca Selys, 1878 y C. lugubris Navás, 1934 son descritas e ilustradas por primera vez usando material de Costa Rica para las dos primeras y de Colombia para la última especie. Se incluye además la descripción de la larva de C. marina Selys, 1868 de especímenes recolectados en Costa Rica para propósitos comparativos. Las especies de Cora son muy similares como larvas, pero se pueden diferenciar dos grandes grupos basado en la forma de las branquias caudales. Las tres especies que se describen pertenecen al mismo grupo y se pueden separar entre ellas usando una variedad de caracteres.

Agrorural Ecosystem Effects on the Macroinvertebrate Assemblages of a Tropical River

Costa Rica is an ideal reference point for global tropical ecology. It has an abundance of tropical forests, wetlands, rivers, estuaries, and active volcanoes. It supports one of the highest known species density (number of species per unit area) [1, 2] on the planet and possesses about 4 % of the world s total species diversity [3]. Because of its tropical setting, it also serves as an important location for agricultural production, including cultivars such as coffee, bananas, palm hearts, and pineapples. The country has also attracted more ecotourists and adventure travelers per square kilometer than any other country in the world [4].

New records of Gerromorpha (Insecta: Hemiptera: Heteroptera) from Costa Rica

The Gerromorpha from Costa Rica are poorly studied, except the Gerridae. Aiming to fill this gap, specimens collected across the country were examined. Lipogomphus leucostictus, Hydrometra alloiona, H. australis, H. huallagana, Microvelia albonotata, M. argentata, M. laesslei, M. mimula, M. panamensis, M. psilonota, M. pulchella, M. signata, and M. torquata are newly recorded from Costa Rica. Presences of Hebrus concinnus, Mesovelia amoena, and Platyvelia brachialis are confirmed. New provincial records are provided for Hebrus consolidus, H. spiculus, Hydrometra caraiba, Mesovelia mulsanti, Mesoveloidea williamsi, Microvelia reflexa, M. schmidti, and Stridulivelia cinctipes.

Description of the larva and pupa of Limnephilus hamifer Flint 1963 (Trichoptera, Limnephilidae) from Costa Rica

The larva and pupa of Limnephilus hamifer Flint 1963 are described and illustrated for the first time. The description is based on material collected and reared from the Cerro de la Muerte mountain range in Costa Rica, and from additional specimens deposited at the Zoological Museum of the University of Costa Rica. The distribution of this species is restricted to high mountain areas of Costa Rica and Panamá and constitutes the most southern distribution of the genus on the American continent.

The water striders (Hemiptera: Heteroptera: Gerridae) of Costa Rica: new species, checklist, and new records

Brachymetra bernaldi Cordeiro, sp. nov. (Hemiptera: Heteroptera: Gerridae) from Heredia, Costa Rica, is herein described, illustrated, and compared with congeners. The new species resembles B. albinervus (Amyot Serville, 1843), but can be separated from it by the weak median carina of the pronotum, male abdominal mediotergite I with weak lateral notches, male abdominal mediotergite VII quadrate, male abdominal segment VIII in natural position almost entirely inserted into the abdominal cavity, and paramere narrow, with acute apex. We also provide the first checklist of the Gerridae of Costa Rica and new records, based on collection material and field sampling. All totaled, 31 species representing 13 genera and six subfamilies are recorded from the country. Five species and the genera Brachymetra Mayr, 1865 and Neogerris Matsumura, 1913 are registered for the first time from Costa Rica, and new provincial records are presented for 15 other species.

The larva of Perissolestes remotus (Williamson & Williamson, 1924) (Zygoptera: Perilestidae)

The larva of Perissolestes remotus is described for the first time based on Costa Rican specimens collected in forested streams with abundant organic matter. It is characterized by a slender, elongated body, with lateral keels on abdominal segments 1–9, and a middorsal row of spines on segments 4–10. We also provide additional notes on the larvae of P. magdalenae using material from Panama. The larva is similar to the only other species of Perissolestes present in Mexico and Central America, P. magdalenae, but can be separated by the articulation of the prementum-postmentum reaching the metacoxa (reaching the mesocoxa in P. magdalenae) and the female gonapophyses exceeding past the posterior margin of S10 (just reaching posterior margin in P. magdalenae). At the generic level, Perissolestes can be differentiated from Perilestes by the presence of abdominal keels on segments 1–9 (from 4–9 in Perilestes) and by having caudal gills with small spines along the medial trachea (spines absent in Perilestes).

The Management of Typha domingensis (Typhaceae) affects Macroinvertebrate Assemblages in the Palo Verde Wetland, Guanacaste, Costa Rica

The Palo Verde wetland, one of the most important places for aquatic organisms in Costa Rica, is currently recovering from an invasive expansion of Typha domingensis (cattail). A monitoring program was designed to understand the potential impacts of different management plans on aquatic fauna and flora. Macroinvertebrates were sampled monthly for one year (Aug 2003–Aug 2004) using an artificial substrate method in three plots: Plot A, T. domingensis has been managed since 1987 by manual and mechanical underwater cutting and posterior grazing; Plot B, T. domingensis has been mechanically crushed since 2002; and Plot C, a homogeneous T. domingensis stand without active management. We identified 112 macroinvertebrate taxa from 53 families and 18 orders. Typha domingensis removal in plots under active management did not increase family or taxa richness. Instead, a greater number of rare taxa persisted in the unmanaged plot, and macroinvertebrate communities differed among plots with less than 60% of taxa shared among them. Furthermore, mean taxa richness was higher in T. domingensis cover (X̄ = 8.56) than in the other vegetation covers (X̄ = 4.6 to 5.54). Macroinvertebrate richness was affected by vegetation cover, sampling date, and depth while abundance was affected by depth and dissolved oxygen. Typha domingensis management is necessary to open areas that allow the development of other vegetation types, a variety of communities of macroinvertebrates, and habitat for birds. However, in order to promote a high macroinvertebrates biodiversity and ensure food sources for waterfowl, the Palo Verde wetland should retain some patches of T. domingensis distributed throughout.

Two new species of Rhagovelia (Hemiptera: Heteroptera: Veliidae) from Costa Rica, with a key and new records from the country

Rhagovelia danpolhemi sp. nov., from the Caribbean Slope of Costa Rica and R. springerae sp. nov., from the northern portion of the country, are described, illustrated, compared with similar species, and included in a key to species recorded from the country. Rhagovelia calopa Drake & Harris, R. spinosa Gould, and R. tantilla Drake & Harris are recorded for the first time from Costa Rica. New provincial records are provided for R. acuminata Bacon, R. angustipes Uhler, R. armata (Burmeister), R. bisignata Bacon, R. crassipes Champion, R. elegans Uhler, R. femoralis Champion, R. solida Bacon, R. spinigera Champion, R. tenuipes Champion, and R. uncinata Champion. Additional distributional information is given for these species and for R. formosa Bacon and R. scabra Bacon.