Polimorfismo morfológico de una población urbana de Pterostichus melanarius (Illiger, 1798) (Coleoptera, Carabidae)

We examined polymorphism in an urban population of the ground beetle Pterostichus melanarius (Illiger, 1798) in forest plantations on the outskirts of Dnipropetrovsk (Ukraine). We took measurements for 130 males and 95 females according to 14 metric, 10 non-metric parameters and 10 indices. According to 13 out of the 14 metric parameters (except for the length of the flight wings) P. melanarius showed a significant sexual dimorphism. The female specimens showed a normal distribution in body length and the males showed a significant positive excess. The 10 most significant body proportions of the ground beetles showed much lower sexual differences (0.26±0.86%) compared to linear measurements (6.56±0.96%). Females and males are practically isomorphic: when one metric parameter decreases, another decreases proportionally. Statistically significant differences between males and females were registered only for the ratio of elytra to length of prothorax, width of elytra to maximum width of prothorax and length of elytra to their width. A highly significant excess was registered in 6 out of 10 assessments of body proportions for females and 5 out of 10 for males. The coefficient of variation is minimal for body proportions and is maximal for metric parameters, which proves the existence of isomorphic differences between P. melanarius males and females. Out of 10 non-metric parameters a statistically significant sexual dimorphism (P=0.01) was registered only for the shape of the front edge of the labrum (males mostly have a slightly concave, and females a strongly concave front edge of the labrum). Using PCA analysis it was established that 45.2% of the morphological variability of the studied population depends upon the individuals’ sex: the whole complex of metric parameters (length and width of head, prothorax, elytra and parts of head, body height) taken together synchronically varies among individuals of different sex. More or less defined groups (morphotypes) were not found among the studied population of P. melanarius. The normal distribution of individuals in the studied population for a range of characteristics was altered by the impact of significant asymmetry or excess in certain features or ratios of metric characteristics. The data obtained can form the basis for monitoring the condition of P. melanarius populations, the individuals of which accumulate a large amount of toxins in conditions of anthropogenic impact.Se ha examinado el polimorfismo de una población urbana del carábido Pterostichus melanarius (Illiger, 1798) en plantaciones forestales de las inmediaciones de Dnipropetrovsk (Ucrania). Se han estudiado 130 machos y 95 hembras mediante 14 parámetros métricos, 10 no métricos y 10 índices corporales. De acuerdo con 13 de los 14 parámetros métricos (a excepción de la longitud de las alas membranosas), P. melanarius mostró un dimorfismo sexual significativo. Las hembras mostraron una distribución normal en la longitud del cuerpo y los machos una diferencia significativa. Las 10 proporciones corporales más significativas de esta especie mostraron diferencias sexuales mucho menores (0,26±0,86 %) que las mediciones lineales (6,56±0,96 %). Las hembras y los machos tienen prácticamente la misma forma: cuando un parámetro indicador disminuye, otro lo hace también proporcionalmente. Se registraron diferencias estadísticamente significativas entre machos y hembras solo para las siguientes razones: longitud de los élitros/longitud del protórax, anchura de los élitros/anchura máxima del protórax y longitud/anchura de los élitros. Una diferencia muy significativa se registró en 6 de cada 10 cálculos de las proporciones corporales para las hembras y 5 de cada 10 para los machos. El coeficiente de variación es mínimo para las proporciones corporales y máximo para los parámetros métricos, lo que demuestra la existencia de diferencias de forma entre machos y hembras de P. melanarius. De los 10 parámetros no métricos, se registró dimorfismo sexual estadísticamente significativo (P=0,01) solo en la forma del borde delantero del labro (los machos en su mayoría tienen una ligera concavidad mientras que las hembras muestran dicho borde muy cóncavo). El Análisis de Componentes Principales (PCA) estableció que el 45,2 % de la variabilidad morfológica de la población estudiada depende del sexo de los individuos: los parámetros métricos (longitud y anchura de la cabeza, protórax, élitros y partes de la cabeza, altura corporal) varían en conjunto sincrónicamente entre los ejemplares de distinto sexo. No se encontraron grupos más o menos definidos (morfotipos) en la población estudiada de P. melanarius. La distribución normal de ciertos caracteres en los ejemplares de la población estudiada se vio modificada por una asimetría significativa o un exceso en ciertas características morfológicas o proporciones métricas. Los datos obtenidos pueden servir de base para el seguimiento del estado de las poblaciones de P. melanarius ya que los individuos acumulan una gran cantidad de toxinas en condiciones de impacto antropogénico

Effect of canopy density on litter invertebrate community structure in pine forests

We investigated the structure of the litter invertebrate community in 141 pine (Pinus sylvestris Linnaeus, 1753) forest sites with five variants of canopy density (30-44, 45-59, 60-74, 75-89 and 90-100%) in the steppe zone of Ukraine. The total number of litter macrofauna specimens collected at each site decreased from an average of 84/100 trap-days in the sparsest stands (30-40% density) to 4-39 specimens/100 trap-days in the forests with a denser canopy. The number of macrofauna species caught in the pitfall traps does not vary significantly with different degrees of canopy density. The Shannon-Weaver and Pielou diversity indexes show increases corresponding to increasing stages of canopy density. The average share of phytophages in the trophic structure of the litter macrofauna does not vary with canopy density. The relative number of saprophages decreases from 54% in the forests with the sparsest canopy to 11-13% in the forests with denser canopies. The relative number of saprophages in pine forests (22%) is lower than that in deciduous forests (40%). The share of zoophages in the trophic structure of the litter macrofauna increases significantly with the increase in the pine forest canopy density (from 21% in the sparsest plots to 59% in the densest). The relative number of polyphages is highest (47-65%) when the canopy density is 45-89%. At canopy densities below or above this range, the share of polyphages in the community decreases to 20 and 24%, respectively. Regardless of canopy density, Formicidae and Lycosidae invariably rank amongst the first three dominant families. Nine families of invertebrates dominate in the pine forest stands with the highest density (90-100%), and 5-7 families dominate in the stands with lower density. For the pine forest litter macrofauna, we have observed an extreme simplification of the community size structure compared with natural and planted deciduous forests of the steppe zone of Ukraine

The impact of some inorganic substances on change in body mass of Tenebrio molitor (Coleoptera, Tenebrionidae) larvae in a laboratory experiment

Addition of low concentrations of metal ions to the diet of saprophagous insects can impact on their metabolism over a short period of time, causing an increase or decrease in their body mass. This article presents a 14-day laboratory experiment evaluating the changes in the body mass of larval stage 3 of Tenebrio molitor (Linnaeus, 1758) induced by adding different inorganic substances (350 mg kg−1 of dry fodder) to the diet of the larvae. Following the addition of inorganic substances to the fodder, the most marked differences compared to the control were observed in the groups which consumed substrate with lead nitrate (the mass of the larvae increased on average by 102.6% compared to increase in mass in the control variant of the experiments), cobalt nitrate (by 96.9%), calcium chloride (by 89.1%) sodium triphosphate (by 86.0%), zinc chloride (by 83.5%). A nonsignificant effect (a tendency of increase in the body mass) on T. molitor larvae was caused by manganese sulfate (by 57.8%), aluminium nitrate (by 57.3%), iron oxide (by 51.5%), barium nitrate (by 47.9%), orthophosphoric acid (by 47.4%), manganese chloride (by 46.5%), calcium carbonate (by 27.7%), iron sulfate (by 24.2%) and ammonium heptamolybdate (by –7.5%). Therefore, 5 out of the 15 studied inorganic substances significantly stimulated the increase in the body weight of T. molitor larvae, and 7 manifested these capacities at the level of tendency (stimulated an increase in body weight averaging 43–58% over the 14-day experiment). The obtained data indicate a necessity for further study on the impact of inorganic pollutants on different stages of insects

Effect of lead and cadmium ions upon the pupariation and morphological changes in Calliphora vicina (Diptera, Calliphoridae)

Modelling the influence of different concentrations of lead and cadmium ions upon a laboratory culture of insects has not been adequately studied. In our research, we assessed the influence of cadmium and lead nitrates at different concentrations (10-2-10-9 М) upon the development of larvae, pupae and imagines of Calliphora vicina Robineau-Desvoidy, 1830 (Diptera: Calliphoridae). We found an acceleration in the development of larvae and an increase in mass of puparia when lead ions were added to the food of the larvae, and decrease in the mass of puparia when cadmium ions were added. We registered nanism and malformation of the fly imagines in experiments with lead and cadmium in the food substrate. We observed that under the influence of the studied heavy metal ions there was a reduced motor activity of the fly larvae at all stages of development, a delay in formation of puparia and a delay in the emergence of imagines in comparison with the control group