Effects of spirodiclofen on the reproductive potential of two-spotted spider mite (Acari: Tetranychidae) ovipositing females

A laboratory bioassay was conducted to evaluate the effects of spirodiclofen on the survival and reproduction of young and mated females of two-spotted spider mite (Tetranychus urticae Koch). The females were sprayed with a series of acaricide concentrations (96, 48, 24, 12, and 6 mg/l) 24-30 h after adult emergence, i.e., at the age most likely to exhibit dispersal behavior and close to their reproductive maximum. The proportions of T. urticae females that survived treatment without symptoms of poisoning were concentration-dependent, ranging between 0.41 and 0.88 (0.96 in the control). With the exception of females that survived 6 mg/l, fecundity of the treated female mites was strongly affected during the exposure, compared to the control. The mean daily fecundity (EL) and mean daily fertility (EH) of surviving females, transferred daily to new leaf disks over the following five days, significantly decreased as spirodiclofen concentrations increased. In treatments with 6 mg/l and 12 mg/l, only the latter concentration significantly reduced both EL and EH, compared to the control. In females that survived 24 mg/l and 48 mg/l, these life history parameters were reduced by over 90%, while treatment with 96 mg/l completely terminated egg-laying. The treated females lived for a significantly shorter time than untreated ones, with the exception of females that survived 6 mg/l. Compared to the control females, gross fecundity (GL) and gross fertility (GH) of the treated females were strongly reduced on the first and second day; from the third day onward, females treated with the lowest concentrations achieved marked recovery, their GL and GH going even above the values in the control. However, net fecundity (NL) and net fertility (NH) of all treated females decreased considerably throughout the trial, indicating that survival rates of these females were lower, compared to the control. Calculated as total sums of gross and net daily schedules within five days, fecundity and fertility significantly decreased as spirodiclofen concentration increased. The two lowest concentrations failed to achieve a significant reduction of GL, while GH, NL, and NH were significantly lower than control values starting with the females treated with 6 mg/L. A high percentage of unhatched eggs, especially during the initial two days after treatment (35-100%), further contributed to the significant reduction in fertility of the females treated with spirodiclofen. All concentrations of spirodiclofen significantly reduced the instantaneous rate of increase. Regression analysis showed a linear population decline with increased acaricide concentrations (y = 1.13 - 0.24x; R2 = 0.91, p < 0.05)

Comparative analysis of sound production between the bighead goby Ponticola kessleri and the round goby Neogobius melanostomus: Implications for phylogeny and systematics.

Divergence in acoustic traits between closely related species can be explained by phylogenetic history. In gobies, phylogenies reconstructed with acoustic signals primarily overlap with studies based on morphological or molecular data. Here, sound production of the two Ponto-Caspian gobies, Neogobius melanostomus and Ponticola kessleri, was recorded in controlled conditions and compared to determine the degree of interspecific acoustic variation across benthophilin gobies. Both species produced tonal-like sounds characterized by unique temporal and spectral properties during agonistic and reproductive intraspecific interactions, while the acoustic comparison revealed that the vocalizations of these two species differ in almost every acoustic property. N. melanostomus vocal structure was characterised by short (c. 100 ms), low-frequency (< 100 Hz) tonal sounds repeated at a relatively faster rate, while P. kessleri sounds appeared as a broadband, downward frequency modulated longer calls (c. 450 ms)

The interaction between the swine infectious diseases agents and low levels of mycotoxins in swine feed

The aim of the paper was to evaluate the possible interaction between the presence of swine infectious diseases and low levels of mycotoxins in swine feed. The material for this research included the samples from three swine farms, where health disorders in different swine categories were detected. The applied research methods included: epidemiological and clinical evaluation, pathological examination, bacteriological and virological laboratory testing and microbiological feed testing, in order to examine the presence of fungi and mycotoxins by the method of thin layer chromatography. Beside this, the molecular diagnostic method, reverse transcripton-polymerase chain reaction (RT-PCR) and viral isolation was included. The obtained results support the existance of positive interaction between the mycotoxins and causative agents of bacterial and viral swine infective diseases

Spider mites and predatory mites (Acari: Tetranychidae, Phytoseiidae) on stone fruit trees (Prunus spp.) in Serbia

The results of a research conducted from 1980 to 2016 of leaf mites of stone fruit trees (Prunus spp.) in Serbia are presented. The species complex of 9 spider mite species and 16 phytoseiid species was recognized on 10 Prunus species. A total of 17 mite species were found on cherry plum (Prunus cerasifera Ehrh.) and blackthorn (Prunus spinosa L.), 16 species were found on sweet cherry (Prunus avium L.), and 13 species were found on plum (Prunus domestica L.). The highest coefficient of constancy among the spider mites was found for Bryobia rubrioculus (Scheuten) (27.9%), and among the phytoseiids for Euseius finlandicus (Oudemans) (58.7%). Very significant positive values of the association index were found for the pairs: Typhlodromus (Typhlodromus) pyri Scheuten-Bryobia angustisetis Jakobashvili, Neoseiulella aceri (Collyer)-Panonychus ulmi (Koch), N. aceri-Bryobia sp., Phytoseius corniger Wainstein-T.(T.) pyri, N. aceri-P. echinus, P. macropilis -Paraseiulus soleiger (Ribaga). Significant positive values were noted for the the pairs P. corniger-Bryobia sp., P. echinus-Bryobia sp., and K. aberrans-P. echinus. Very significant negative index values were detected for the pairs E. finlandicus-K. aberrans and E. finlandicus-P. macropilis, and a significant negative index of association for the pair A. andersoni-A. viennensis

Species complexes of predatory mites and spider mites (Acari: Phytoseiidae, Tetranychidae) on cultivated and wild apple trees in Serbia

The species complexes of leaf-inhabiting mites on apples were studied on actively cultivated and neglected apple orchards as well as on wild apple trees in Serbia, from 1981 to 2013. Thirty-nine species of 11 families were found on Malus domestica Borkh; 25 species of 6 families were found on Malus sylvestris (L.) Miller and Malus pumila Miller. A complex of 18 phytoseiid and 9 spider mite species was detected. Four phytoseiid and three spider mite species were found in commercial apple orchards, 13 phytoseiid and 5 spider mite species in neglected apple stands, and 12 phytoseiid and 7 spider mite species in forest habitats. Predatory mites Euseius finlandicus (Oudemans) and Amblyseius andersoni (Chant) and spider mites Panonychus ulmi Koch and Amphitetranychus viennensis (Zacher) had the highest constancy of occurrence. Positive and significant (or very significant) association was detected for 16 pairs of species. The pairs of phytoseids-spider mites Amb. andersoni-Pan. ulmi, Amb. andersoni-Tetranychus turkestani Ugarov et Nikolskii, and Typhlodromus (Anthoseius) rhenanus (Oudemans)-Te. turkestani had the highest interspecific association indices. Higher mite diversity was found on wild than on cultivated apples, and higher diversity on neglected than on cultivated apples. The complexes of phytoseiids and spider mites had uniform composition in the cultivated orchards, while their composition in the neglected stands was nonuniform and extremely heterogeneous on the wild apple trees