High-elevational occurrence of two tick species, Ixodes ricinus and I. trianguliceps, at their northern distributional limit

Background: During the last decades a northward and upward range shift has been observed among many organisms across different taxa. In the northern hemisphere, ticks have been observed to have increased their latitudinal and altitudinal range limit. However, the elevational expansion at its northern distribution limit remains largely unstudied. In this study we investigated the altitudinal distribution of the exophilic Ixodes ricinus and endophilic I. trianguliceps on two mountain slopes in Norway by assessing larval infestation rates on bank voles (Myodes glareolus).Methods: During 2017 and 2018, 1325 bank voles were captured during spring, summer and autumn at 10 trapping stations ranging from 100 m to 1000 m.a.s.l in two study areas in southern Norway. We used generalized logistic regression models to estimate the prevalence of infestation of both tick species along altitude, considering study area, collection year and season, temperature, humidity and altitude interactions as extrinsic variables; and host body mass and sex as intrinsic predictor variables.Results: We found that both I. ricinus and I. trianguliceps infested bank voles at altitudes up to 1000 m.a.s.l., which is a substantial increase in altitude compared to previous findings for I. ricinus in this region. The infestation rates declined more rapidly for I. ricinus compared to I. trianguliceps, indicating that the endophilic ecology of I. trianguliceps may provide shelter from limiting factors tied to altitude. Seasonal effects limited the occurrence of I. ricinus during autumn, but I. trianguliceps was found to infest rodents at all altitudes during all seasons of both years.Conclusions: This study provides new insights into the altitudinal distribution of two tick species at their northern distributional limit, one with the potential to transmit zoonotic pathogens to both humans and livestock. With warming temperatures predicted to increase, and especially so in the northern regions, the risk of tick-borne infections is likely to become a concern at increasingly higher altitudes in the future.

New records of Tachybaptus dominicus (Linnaeus, 1766) (Aves, Podicipedidae) south of its currently known distribution in Argentina

We report on 4 records of the Least Grebe, Tachybaptus dominicus (Linnaeus, 1766), to the south of its theoretical distributional limit in Córdoba Province, Argentina. In recent years, these records and others uploaded to citizen science platforms suggest that this species’ distribution extends south of its currently known range.

Temperature-dependent seminal recovery in the southern king crab Lithodes santolla

Male-biased fishery management can provoke depletion of seminal reserves, which is the primary cause of sperm limitation. Therefore, identifying factors which contribute to the vulnerability to depletion of seminal reserves is a priority. The present study aimed to determine the effect of temperature on the recovery rate of sperm and seminal reserves after their depletion in Lithodes santolla , an important fishery resource in southern Chile. Sperm and seminal reserves were not fully recovered within 30 days. Temperature significantly affected seminal recovery: after 30 days the recovery index increased to 40% and 21% at 9°C and 12°C, respectively. The twice as fast seminal recovery at 9°C may be explained by the zone of origin of the individuals in this study (northern distributional limit), and 12°C may be close to the threshold of temperature tolerance. Lithodes santolla populations subject to intense male-only fisheries may be vulnerable to depletion of seminal reserves and a climate change scenario could additionally aggravate the risk of seminal depletion in L. santolla in its northern distributional limit.

LAS ARDILLAS DE NICARAGUA (RODENTIA, SCIURIDAE)

ResumenActualizamos el conocimiento de la riqueza, distribución y taxonomía de las ardillas nicaragüenses, con tres géneros y seis especies: Glaucomys volans, Microsciurus alfari, Sciurus deppei, Sciurus granatensis, Sciurus richmondi y Sciurus variegatoides. Una es típica del bosque de coníferas del norte, G. volans; S. deppei de las montañas del norte y el Caribe; tres son propias del bosque Caribeño, M. alfari, S. granatensis y S. richmondi; y S. variegatoides se distribuye en todo el país con seis subespecies: S.variegatoides dorsalis del Pacífico y zona central; S. variegatoides adolphei del noroeste; S. variegatoides underwoodi y S. variegatoides boothiae del norte; S. variegatoides belti y S. variegatoides thomasi del Caribe. Son endémicas, S. richmondi y la subespecie S. variegatoides adolphei. Microsciurus alfari y S. granatensis presentan su límite norte en el sureste y G. volans presenta su límite sur en el norte. La lista roja nacional enlista tres especies en riesgo: S. richmondi y G. volans en peligro de extinción y M. alfari como amenazada; a nivel mundial se cataloga a S. richmondi como casi amenazada.Palabras clave: amenazado, endémico, Microsciurus alfari, Glaucomys volans, Sciurus deppei, S. granatensis, S. richmondi, S. variegatoides.AbstractThe updated richness, taxonomy, and distribution of Nicaraguan squirrels includes three genera and six species: Glaucomys volans, Microsciurus alfari, Sciurus deppei, Sciurus granatensis, Sciurus richmondi and Sciurus variegatoides. Glaucomys volans is typical of northern pine forest; S. deppei of northen mountains and Caribbean forest; three are restricted to Caribbean forest, M. alfari, S. granatensis and S. richmondi; whereas S. variegatoides is found throughout Nicaragua with six subespecies: S. variegatoides dorsalis pacific and central zone; S. variegatoides adolphei northeast; S. variegatoides underwoodi y S. variegatoides boothiae north; S. variegatoides belti and S. variegatoides thomasi is found on Caribbean slope. Sciurus richmondi and the subspecies S. variegatoides adolphei are endemic to Nicaragua. Microsciurus alfari and S. granatensis have their northernmost distributional limit in Southeastern Nicaragua, while the southern limit G. volans is in Northern Nicaragua. The Nicaraguan red list contains: S. richmondi and G. volans as endangered and M. alfari and S. richmondi as near endangered.Key words: endemic, endangered, Microsciurus alfari, Glaucomys volans, Sciurus deppei, S. granatensis, S. richmondi, S. variegatoides.