Imelda Martinez-Morales

The anatomy of the internal male reproductive systems of 12 species of Melolonthinae (Phyllophaga, Chlaenobia, Macrodactylus, Isonychus), six species of Dynastinae (Cyclocephala), and three species of Rutelinae (Paranomala) (Coleoptera, Scarabaeoidea) of Mexico are described. A total of 350 male specimens representing 21 species were collected. From each species, the reproductive systems were obtained by micro-dissection, placed in a liquid fixative, stained, and drawn to scale. The internal genitalia of each species was described and compared among the species examined. The reproductive system of the Melolonthinae species is comprised of two testicles, each with six follicles, two deferent ducts, two accessory glands, two glandular ducts, an ejaculatory duct, and the aedeagus (not described for any of the species examined). The number of testicular follicles per testicle is as reported in different species of other Scarabaeoidea subfamilies. The length of the accessory glands and the ejaculatory duct varies in the species studied. The ejaculatory bulb is present in all of the species of Dynastinae and Rutelinae examined but in only three species of Melolonthinae.

The reproductive biology of Euoniticellus intermedius (Reiche) was studied using insects collected in Quiahuixtlan, Veracruz, Mexico, that were kept under controlled environmental conditions (temperature: 26.9 °C ± 0.09; relative humidity: 69.75% ± 1.7; photoperiod: 14D-10N). The reproductive systems of both sexes—similar to those described for other species of Scarabaeinae—are described. Females lay two eggs each day. Their fecundity is 111 ± 15 eggs. The lifespan of this species is 30 to 60 days. Development from egg to imago ranges from 25 to 28 days. The three larval instars are described.

Canthon imitator Brown 1946 se registra por primera vez en el Municipio de Papantla, Veracruz, México. Este es el registro más meridional que se tiene de esta especie. Es un escarabajo estercolero rodador, diurno, abundante en el sitio de colecta de mayo a julio. Las hembras tienen sólo el ovario izquierdo con una ovariola. Ovipositan un solo huevo cada 4 a 5 días en una bola nido piriforme. Los machos tienen dos testículos, cada uno con seis folículos testiculares esféricos. El desarrollo hasta imago dura aproximadamente 30 días como en otras especies de Canthon estudiadas.

Pedro Reyes Castillo, egresó de la Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional de México. Fue un pilar importante en la formación y seguimiento del Instituto de Ecología A. C. de Xalapa, Ver. Intervino en la formación de las Reservas de Biosfera en México. Se dedicó toda su vida a la entomología, en particular al estudio de los escarabajos del grupo de Passalidae, por lo que fue reconocido a nivel internacional. Fue un gran ser humano que amó y trabajó incansablemente para la biología y la conservación de la biodiversidad. Publicó más de 200 trabajos, describió muchas especies y formó alumnos de posgrado. Nos dejó el 20 de marzo de 2018.

Two distinct experiments were carried out to assess the trans-generational and within-generational effects of the parasiticides ivermectin and moxidectin to dung beetles (Coleoptera: Scarabaeidae). In the first experiment, the fertility of Euoniticellus intermedius (Reiche) (Scarabaeinae) was assessed for individuals developing in dung containing 10 µg ivermectin/kg fresh dung, a residue concentration previously shown to be sublethal to larval development. Our results showed that the fertility of adults exposed to these residues as larvae was unaffected. In the second experiment, the fertility of Agrilinus constans (Duftschmid) (Aphodiinae) was determined after females were allowed to feed for three weeks on dung containing different concentrations of moxidectin residues (five concentrations ranging from 0.32–32.00 mg/kg dry dung). The fertility of females was not affected, regardless of the concentration to which they were exposed, even when they were exposed to high moxidectin residues that killed all the offspring. The combined findings of these two experiments emphasise that sublethal effects should be included in models that assess the nontarget effects of faecal residues to insects breeding in dung of livestock treated with veterinary medicinal products.

The phenology of the dung beetle Euoniticellus intermedius (Reiche) was studied under field conditions, along with two main environmental services: the quantity of dung buried per beetle under controlled insectarium conditions; and the monthly abundance of nematode eggs in cattle dung that had not been treated with anti-helminthics. Euoniticellus intermedius was very abundant during the rainy season. Similarly, the highest number of nematode eggs was found during the rainy season. Recently emerged E. intermedius in the laboratory buried daily less than half the dung (0.91 ± 0.16 grams) buried by mature individuals (2.17 ± 0.04 grams). During the rainy season, each recently emerged beetle buried an average of 53.7 nematode eggs, and each mature beetle buried 128 eggs. During the dry season, each recently emerged beetle buried on average 4.6 eggs, whereas mature beetle buried on average 10.9 eggs. Our results show that the quality of environmental services provided by E. intermedius is dependent on...

Se estudiaron los escarabajos estercoleros en un pastizal tropical en Veracruz, México. Se exploró el reemplazo de especies a escala interanual y estacional. Los resultados indican que las poblaciones de algunas especies se encuentran en regresión, incluyendo las especies introducidas en 1980. Los cambios observados en la comunidad de escarabajos estercoleros pueden ser explicados en parte por el uso de agroquímicos y drogas desparasitantes que se comenzaron a emplear en el área a partir de 1980. Quizás el inadecuado uso de estas sustancias refleja el actual número de especies y la abundancia de escarabajos estercoleros. Se propone implementar medidas legales orientadas al uso más adecuado de medicamentos veterinarios y plaguicidas con el fin de conservar estos organismos clave involucrados en procesos ecológicos y en servicios ambientales importantes. La pérdida de esta entomofauna puede ocasionar severos estragos ambientales, incluyendo efectos sobre los humanos.

This study assesses the effects of the veterinary medical product ivermectin (IVM) in a range of concentrations on adult reproductive physiology and larval mortality of the dung beetleEuoniticellus intermedius(Reiche) (Coleoptera: Scarabaeidae). The ecotoxicological tests comprised eight treatments, including two controls and six increasing ivermectina concentrations (3.16, 10.0, 31.6, 63.2, 100, and 316 µg IVM/kg fresh dung). After 10 days of exposure, the females were dissected and the brood balls counted (fecundity). The brood balls were opened 15 days later and live larvae were counted to estimate larval mortality. Ivermectin altered the morphology of the ovary and stopped vitellogenesis, causing oocyte resorption and thus decreasing fecundity. The 30% threshold of decline in fecundity was reached at 115.9 µg IVM/kg dung, with no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) values of 10.0 and 31.6 µg IVM/kg dung, respectively. Larval sensitivity to ivermectin was higher, with a lethal concentration required to kill 50% of the population of 85.9 μg IVM/kg dung, and NOEC and LOEC of 3.16 and 10.0 µg IVM/kg dung, respectively. After cattle were treated with ivermectin at the recommended dose, the ivermectin concentration in their dung during the two first weeks after administration far exceeded the thresholds determined forE. intermedius.