Oviparous Females Research Articles

Higher locomotor costs of pregnancy in viviparous compared to oviparous common lizards (Zootoca vivipara).

Pregnancy is a physiological cost of reproduction for animals that rely on fleeing to avoid predators. Costs of reproduction are predicted to differ between alternative reproductive strategies or modes, such as egg-laying (oviparity) or live-bearing (viviparity). However, disentangling the factors that comprise this cost and how it differs for oviparous or viviparous females is challenging due to myriad environmental, biological, and evolutionary confounds. Here, we tested the hypothesis that costs of pregnancy differ between oviparous and viviparous common lizards (Zootoca vivipara). We predicted that the degree of locomotor impairment during pregnancy and therefore the cost of reproduction would be higher in viviparous females. We conducted our experiment in a hybrid zone containing oviparous and viviparous common lizards. Due to the common environment and inclusion of hybrid individuals, we could infer whether differences were inherent to parity mode. We found that the average and maximum running speed of pregnant females was slower than after they had given birth or laid eggs. Viviparous females experienced an additional pregnancy weight burden and for a longer time period, but were not slower at running than pregnant oviparous females. In addition, we found a parity mode-specific effect of reproductive investment; producing larger clutches was costlier for the locomotor performance of viviparous females for reasons other than the mass increase. Locomotor costs were found to be intermediate in hybrid females, indicating that they are specific to each reproductive mode. Our study shows that viviparous females experience an additional physical and physiological cost of pregnancy and reproductive investment. This two-fold cost implies that viviparous females modulate resource allocation decisions and/or adjust their behavioural responses that result from locomotor impairment.

Corticosterone treatment results in fat deposition and body mass maintenance without effects on feeding behaviour or immunity in female lizards (Tropidurus catalanensis)

Throughout life, animals must maintain homeostasis while coping with challenging events. The period after reproduction can be challenging for oviparous females to maintain homeostasis since they direct most of their energy stores to vitellogenesis, possibly increasing the vulnerability to stressors. Changes in glucocorticoids' (GC) secretion promote various behavioural and physiological adjustments daily and to restore balance after facing stressors. However, when GC are elevated for extended periods, which usually occurs in response to chronic exposure to stressors, they can affect feeding behaviour and suppress the immune function. We aim to elucidate the effects of chronic corticosterone (CORT) exposure on feeding behaviour, body condition and immune function in female lizards, Tropidurus catalanensis, in the post-reproductive period. Thirty animals were divided into three groups: 1. Control (no experimental procedure performed); 2. Empty Implant (animals implanted with empty silastic tube); and 3. CORT Implant (animals implanted with silastic tube filled with CORT, with a chronic continuous release for at least a week). CORT plasma levels feeding behaviour, body condition (body index [BI] and fat index [FI]), leukocyte count, and several immune function variables (bacterial killing ability [BKA], hemagglutination titer, phytohemagglutinin [PHA] immune challenge and leukocyte count) were evaluated. After implantation, CORT treated animals maintained stable body mass through the experiment, while Control and Empty Implant groups displayed weight loss. In the CORT treated animals, there was also a positive relation between BI and FI, and higher FI when compared to groups 1 and 2. No effects of CORT were observed on feeding behaviour nor on the immune function.

Taxonomic Revision of the Nearctic Genus Drepanaphis Del Guercio (Hemiptera, Aphididae: Drepanosiphinae).

The Nearctic aphid genus Drepanaphis Del Guercio, 1909, the largest within the subfamily Drepanosiphinae (Hemiptera: Aphididae), is characterised by distinctive dorsal abdominal tubercles. This study presents a comprehensive taxonomic revision of the genus, expanding the recognised species to 18, including the newly described Drepanaphis robinsoni Malik sp. nov. Detailed descriptions and figures for 44 morphs, encompassing alate viviparous females, oviparous females and males, are provided, with new identification keys for all known species and morphs. The sexual morphs of 15 species, particularly oviparous females, are documented for the first time. Morphometric and principal component analyses (PCA) are employed to distinguish the studied taxa. This study identifies and corrects numerous misidentifications in museum collections, previously labelled as D. acerifoliae, D. choanotricha, D. kanzensis, D. knowltoni, D. parva, D. sabrinae or D. tissoti. Furthermore, it revalidates the distinct status of D. nigricans and D. tissoti, which had been synonymised in earlier works. Current range maps for all species and images of key morphological features obtained through light and scanning electron microscopy are also presented, providing a more complete understanding of this understudied genus.

Self-Recognition and Allorecognition Mechanisms Exert a Significant Influence on the Sex Allocation Patterns of the Pea Aphid.

The mechanism controlling sex allocation in the pea aphid, Acyrthosiphon pisum (Harris), remains a crucial yet unresolved issue in the field of evolutionary ecology. This study aims to assess the influence of the presence of both self and non-self clones, along with juvenile hormone III (JH III) titer, on the sex allocation of aphid offspring. To this end, red and green clones were utilized as experimental subjects, and the agar method was employed. Initially, three distinct experimental treatments were established using sexuparae, and the daily offspring count and sex allocation in each treatment zone were recorded. Subsequently, an additional experimental condition involving mixed-clone treatments was introduced. This procedure entailed the transfer of a single sexupara and 20 oviparous females from either the red (1G + 20Rov) or green clone (1G + 20Gov) onto a leaf on agar medium. Simultaneously, a control setup with a new sexupara (1G) was established. Three days following sexupara production, a dose of 0, 25, or 50 ng of JH III was applied to the aphids' abdomens. Subsequently, the titers of JH III in the sexuparae across each treatment group were quantified, and the extent of sex allocation was tallied. The findings demonstrated pronounced disparities in sex allocation among the various treatments and, notably, a substantial increase in the total offspring and oviparous number in the mixed-clone treatment group. The effects of mixed-clone treatment on the sex allocation patterns of the sexupara progeny could be determined by the application of exogenous JH III, indicating that JH may mediate the effects of mixed-clone treatment on sex allocation. Consequently, it can be concluded that A. pisum sexuparae possess the capability to modulate their sex allocation in response to the nature of adjacent competitor clones, thereby demonstrating a variety of sex allocation patterns. Throughout this process, JH III plays a pivotal role.

Features of the vital activity of cereal aphids in the North-West of Russia

The publication presents data on long-term monitoring of the dynamics of the number of cereal aphids on spring grain crops in the Pushkinsky district of St. Petersburg and the Tosnensky district of the Leningrad region. The appearance of winged parthenogenetic females in the fields in the biotope of grain crops was noted in the first decade of June, the maximum number of aphids - in the second decade. Over the years of observations, outbreaks of mass reproduction were in 1999, 2002, and 2021. The analysis is carried out of the dependence of the number of aphids Rh. padi on the weather conditions of the region. The correlation between the number of aphids on wheat plants and the average monthly April air temperatures was low (r= 0.31), it was higher between the number of insects and the June average monthly air temperatures (r=0.57). At the same time, the average monthly air temperature in April and June 1999 and 2002 were higher than the average long-term indicators. This indicator turned out to be the most effective between the sum of effective temperatures for the spring-summer period (April May, June) and the number of aphids (r= 0.77). The correlation coefficient between the amount of precipitation during this period and, accordingly, the number of aphids turned out to be negative (– 0.6). It is assumed that the degree of pest population of plants in the summer period depends on the number of eggs laid by oviparous females in the previous autumn. In our studies, the correlation coefficient between these indicators was 0.52. One of the most important entomophages of cereal aphids is the beetle Coccinella septempunctata L. Over the years of observations, the number of predators varied from 0.2 to 5 individuals per 1 model site. During the years of mass reproduction of aphids in 2002 and 2021, the number of coccinellids per model site was low and equal to 0.2-0.5. The large grass aphid Sitobion avenae F. appears in the fields of the region in early July. The largest number of species was recorded in 2016, 2020,2022. In the experiments of 2022, the insect preferred spring wheat and oats, compared with barley.

Hitherto unknown sexual morphs of Brachysiphoniella montana (van der Goot, 1917) (Hemiptera: Aphididae).

Here, we describe the hitherto unknown sexual morphs (oviparous females and males) of Brachysiphoniella montana (van der Goot, 1917) (Aphididae: Aphidinae: Macrosiphini). Oviparous females and males from the Republic of Korea are described and illustrated in details. Descriptions of sexual morphs of this species confirm the holocyclic life cycle of Brachysiphoniella in areas with cooler months. Notes about distribution and host plants of the species are also given.

A new species of Metopolophium Mordvilko, 1914 (Hemiptera: Aphididae: Aphidinae) on Rosa beggeriana from Iran

A new species of the genus Metopolophium Mordvilko, 1914 (Hemiptera: Aphididae: Aphidinae: Macrosiphini) is described and illustrated. Apterous and alate viviparous females, oviparous females, and apterous males of Metopolophium rogeri sp. nov. on Rosa beggeriana (Rosaceae) are collected from Kerman Province, Iran. The new species is morphologically most similar to M. alpinum Hille Ris Lambers, 1966, but is characterized by the low ratio of processus terminalis to basal segment of antennal segment VI, high ratio of siphunculus to cauda length and the presence of many more accessory setae on the ultimate rostral segment. This holocyclic aphid is monoecious and not attended by ants. The biometric data are given, and the key to the aphids associated with Rosa species in Blackman and Eastop (2021) is modified to accommodate the new species.

The genus Aphis (Hemiptera, Aphididae) living on Asteraceae species in southern South America: Argentina and Chile, with five new species.

In the whole of Argentina and Chile, southern South America in this paper, 20 species of the genus Aphis hosted in species of Asteraceae were known; eleven of them are native South American, and those introduced are mostly polyphagous and widespread. The Chilean regions and the Argentine provinces in which each one of them is known, as well as the host plants on which it has been recorded, are listed. New data of 15 of them are presented, with several first records in different Argentine provinces or hosted on diverse plants: The knowledge of A. conspicua and A. fuentesi, which were recently described living on species of Baccharis, is improved from specimens respectively collected on Senecio and Gutierrezia. A. rogerblackmani Nieto Nafra, Ortego Mier Durante sp. n. is described from apterous and alate viviparous females, oviparous females and males collected on Baccharis in Argentina. Other four species are described from apterous and alate viviparae: A. gutierreziae Ortego, Mier Durante Nieto Nafra sp. n., collected on species of Gutierrezia in Argentina, A. hyalis Mier Durante, Nieto Nafra Ortego sp. n., collected on Hyalis argentea in Argentina, A. pulverea Nieto Nafra, Moreno-Gonzlez Ortego sp. n., collected on species of Senecio in Chile and Argentina, and A. sanrafaelina Ortego, Mier Durante Nieto Nafra sp. n., collected on Tagetes mendocina, Thymophylla pentachaeta and Pectis odorata in Argentina. The intraspecific diversity of Aphis pulverea has been analysed by a principal component analysis followed by hierarchical clustering of principal components. An identification key to viviparous females of the species of Aphis hosted in Asteraceae and known in southern South America is presented.

Revision of the aphid subgenus Ramitrichophorus Hille Ris Lambers of genus Macrosiphoniella (Hemiptera, Homoptera: Aphididae, Macrosiphini), with redescriptions of all known species and identification keys.

Revision of the aphid subgenus Ramitrichophorus of genus Macrosiphoniella with redescriptions of all known species has been made. Geographical points of species registrations are listed. All known data on the biology of the studied species have been specified and analyzed. It was established that Macrosiphoniella (Ramitrichophorus) paradoxa (Bozhko, 1957) (syn. n.) is a synonym of Macrosiphoniella (Ramitrichophorus) hillerislambersi Ossiannilsson, 1954. It was confirmed that Macrosiphoniella nikolajevi Kadyrbekov, 1999 does not belong to the subgenus Ramitrichophorus. The first descriptions of males and oviparous females of M. (R.) hillerislambersi and M. (R.) medvedevi (Bozhko, 1950), and also alate viviparous females and oviparous females of M. (R.) janckei Brner, 1939 are given. Identification keys to the species of the subgenus is proposed. A possible way of the formation of the subgenus and the speciation that took place in it are discussed.

Morphology, molecular phylogenetics, and DNA barcoding revealed a new unusual species of the aphid genus Pleotrichophorus from the USA (Insecta, Hemiptera: Aphididae).

Here, we present the descriptions of a new aphid species in the genus Pleotrichophorus Brner, 1930 (Hemiptera: Aphididae: Macrosiphini), found by Kenneth L. Hibbard, inspection supervisor for the Florida Department of Agriculture and Consumer Services, Division of Plant Industry. It is associated with Euthamia graminifolia (L.) Nutt. (Asteraceae) a native plant species in Florida, USA. Apterous and alate viviparous and oviparous females of Pleotrichophorus blackmani sp. n. are described and illustrated using light and scanning electron microscopy (SEM). SEM images of apterous viviparous female of Pleotrichophorus glandulosus (Kaltenbach, 1846), type species of the genus Pleotrichophorus, are given for the first time. Taxonomic notes are given, and an updated key to the apterae of the Euthamia-feeding aphids is provided. A multigene phylogenetic analyses of two New World Pleotrichophorus species places the genus in the tribe Macrosiphini sensu stricto. Pleotrichophorus glandulosus, the type species of the genus, was described from Germany. European specimens of P. glandulosus from France had similar molecular sequences to both Florida species, strongly suggesting that the new species belongs in Pleotrichophorus. COI and gnd sequence data indicate that P. blackmani sp. n. can be identified reliably by DNA barcodes.

Dopamine pathway characterization during the reproductive mode switch in the pea aphid

Aphids are major pests of most of the crops worldwide. Such a success is largely explained by the remarkable plasticity of their reproductive mode. They reproduce efficiently by viviparous parthenogenesis during spring and summer generating important damage on crops. At the end of the summer, viviparous parthenogenetic females perceive the photoperiod shortening and transduce this signal to their embryos that change their reproductive fate to produce sexual individuals: oviparous females and males. After mating, those females lay cold-resistant eggs. Earlier studies showed that some transcripts coding for key components of dopamine pathway were regulated between long days and short days conditions suggesting that dopamine might be involved in the transduction of seasonal cues prior to reproductive mode switch. In this study, we aimed at going deeper into the characterization of the expression dynamics of this pathway but also in the analysis of its functional role in this context in the pea aphid Acyrthosiphon pisum. We first analysed the level of expression of ten genes of this pathway in embryos and larval heads of aphids reared under long days (asexual producers) or short days (sexual producers) conditions. We then performed in situ hybridization experiments to localize in embryos the ddc and pale transcripts that are coding for two key enzymes in dopamine synthesis. Finally, Using CRISPR-Cas9 mutagenesis in eggs produced after the mating of sexual individuals, we targeted the ddc gene. We could observe strong melanization defaults in ddc mutated eggs, which confidently mimicked the Drosophila ddc phenotype. Nevertheless, such a lethal phenotype did not allow us to validate the involvement of dopamine as a signaling pathway necessary to trigger the reproductive mode switch in embryos.

Ploidy dynamics in aphid host cells harboring bacterial symbionts

Aphids have evolved bacteriocytes or symbiotic host cells that harbor the obligate mutualistic bacterium Buchnera aphidicola. Because of the large cell size (approximately 100 μm in diameter) of bacteriocytes and their pivotal role in nutritional symbiosis, researchers have considered that these cells are highly polyploid and assumed that bacteriocyte polyploidy may be essential for the symbiotic relationship between the aphid and the bacterium. However, little is known about the ploidy levels and dynamics of aphid bacteriocytes. Here, we quantitatively analyzed the ploidy levels in the bacteriocytes of the pea-aphid Acyrthosiphon pisum. Image-based fluorometry revealed the hyper polyploidy of the bacteriocytes ranging from 16- to 256-ploidy throughout the lifecycle. Bacteriocytes of adult parthenogenetic viviparous females were ranged between 64 and 128C DNA levels, while those of sexual morphs (oviparous females and males) were comprised of 64C, and 32–64C cells, respectively. During post-embryonic development of viviparous females, the ploidy level of bacteriocytes increased substantially, from 16 to 32C at birth to 128–256C in actively reproducing adults. These results suggest that the ploidy levels are dynamically regulated among phenotypes and during development. Our comprehensive and quantitative data provides a foundation for future studies to understand the functional roles and biological significance of the polyploidy of insect bacteriocytes.

Variable impacts on reproductive energetics may render oviparous squamates more vulnerable to climate warming than viviparous species

Squamate reptiles exhibit two reproductive modes: oviparity and viviparity. Existing large‐scale studies suggest that viviparous species are more vulnerable to climate warming based on viviparous species occupying relatively colder environments, which are predicted to decline in availability under climate warming. However, oviparous and viviparous squamates are geographically widespread and their distributions often overlap. Are oviparous or viviparous squamates more vulnerable to climate warming when they inhabit similar thermal environments? We used Sceloporus lizards in North America as a model system to predict the impact of climate warming on oviparous and viviparous species in sympatric zones. We used mechanistic models to quantify the changes in maternal energy balance (MEB) and offspring energy balance (OEB) under a climate warming scenario. We then projected the fitness impacts of future climate warming based on estimates of MEB and OEB. Under a climate warming scenario (RCP8.5), oviparous females are predicted to increase reproductive frequency more than viviparous females, which restricts time for postpartum energy accumulation before the end of the season and decreases MEB. Under climate warming, OEB of oviparous species increased more than viviparous species, but the increases were less geographically widespread. Interestingly, the developmental success and OEB of oviparous species are predicted to decline at some sites under climate warming, which is not predicted to happen for viviparous species. Our results highlight that oviparous species will respond more variably to climate warming than viviparous species. More specifically, oviparous species in hot areas with high temperature variation may be especially vulnerable under climate warming compared to sympatric viviparous species.

Аge structure and fecundity of the noble crayfish populations in abandoned quarries

The population of noble crayfish (Astacus astacus) was researched in quarries of an old brick plant in Molodechno district of Minsk region. Rare disappearing noble crayfish was found in 10 closed quarries. The presence of crayfish in closed quarries that are not connected with watercourses indicates that these populations were created by man. The population of noble crayfish in the quarries of an old brick factory is characterized by a high number. The average catch by eel traps was 1.31 ± 0.77 individuals/trap/day. Crayfish in the first and second year of life grew faster in quarries than in other habitats, but subsequently the average size of individuals in the quarry was smaller in comparison with the general model of noble crayfish growth in Belarus. Individuals that were older than 6 years have not been found in quarries. This indicates that there are factors that determine high mortality rate in older age groups. However, favorable conditions for the growth of juveniles allow the population to maintain their numbers at a high level. The reason for this phenomenon remains unknown. The size of noble crayfish individuals reaching puberty and the fertility is comparable to those from other habitats. In the quarry, the minimum length of an oviparous female was 7.2 cm. Egg-laying females in the 7.0-7.9 cm size class were 16.7 %, in the 8.0-8.9 cm size class - 38.8, in the 9.0-9.9 cm size class - 70.6 %, in the size class of 10.0-10.9 cm all the females were oviparous.The population of noble crayfish from the quarries of Molodechno district should be considered as donor population for carrying out resettlement into the water bodies of the river Neman.

APHIS CORDUBENSIS SP. N. (HEMIPTERA APHIDIDAE) LIVING ON ABUTILON MEGAPOTAMICUM (MALVACEAE) FROM CORDOBA PROVINCE (ARGENTINA)

Aphis cordubensis sp. n. (Hemiptera: Aphididae) is described from apterous and alate viviparous females, oviparous females and males collected in Villa Carlos Paz (Córdoba, Argentina) on Abutilon megapotamicum. A summarized identification key for apterous viviparae of Aphis species recorded worldwide on Malvaceae is presented. The diagnostic features allowing to differentiate the new species from the Aphis species known in South America are presented. The new species should be able to live in Argentina, Brazil and Uruguay on wild and cultivated plants of Abutilon and perhaps on other genera of Malvaceae. The species is potentially invasive and trade and cultivation in gardens and plant nurseries of Abutilon and close genera must be monitored.

Seasonal changes of biological condition and reproductive cycle of hampback shrimp <i>Pandalus hypsinotus</i> (Caridea, Pandalidae) in the Tatar Strait

Research and commercial trawl catches of humpback shrimp Pandalus hypsinotus from the Tatar Strait (Japan Sea) in 2004–2020 were investigated, with bioanalysis of about 45 thousand specimens. Average timing of group molting, spawning, and eggs laying are determined, terms of gonads and eggs development are estimated. Prespawning and molting of the females occur between January-April, with the peaks in early February and middle February, respectively. All oviparous females have 30–40 days to lay eggs, and molt during 50–55 days; the peak of the eggs laying occurs in late June. The males molt in July-August, afterwards the largest individuals change gender and new intersexes are formed. The males have the second molting in October-December, with the peak in late November. In January, after finish of the males molting, a new annual reproduction cycle starts from the prespawning molting of females. Both vitellogenesis and embryogenesis are observed through the year, though females with developing gonads prevail from August to January (because of a long time span between winter and summer moltings while the egg carrying continued 15 months) but oviparous females — from February to July. The individual reproductive cycle of Pandalus hypsinotus in the Tatar Strait lasts 24 months, with 9 months of vitellogenesis (quick growth of gonads) and 15 months of embryogenesis. During the 2-year reproductive cycle, most of females pass through the following stages: i) gonads development (just after eggs laying) when almost all oviparous females (up to 95 % in May) have green gonads under carapace that corresponds to the stage of development «eggs laid — gonads weakly developed»; ii) summer molting from August when females lose hairs on pleopods and the gonads growth accelerates; iii) respawning in January-March (together with the firstly spawning intersexes, with slight delay of the latter); iv) initial developing of eggs during summer; v) stage of «eyed eggs» from December to March; and vi) eggs laying and molting from late March to late May; then the 2-year reproductive cycle repeats.

Progress in the characterization of insulin-like peptides in aphids: Immunohistochemical mapping of ILP4

Aphids were the first animals described as photoperiodic due to their seasonal switch from viviparous parthenogenesis to sexual reproduction (cyclical parthenogenesis) caused by the shortening of the photoperiod in autumn. This switch produces a single sexual generation of oviparous females and males that mate and lay diapausing cold-resistant eggs that can overcome the unfavourable environmental conditions typical of winter in temperate regions. Previous studies have hinted at a possible implication of two insulin-like peptides (ILP1 and ILP4) in the aphid seasonal response, changing their expression levels between different photoperiodic conditions. Moreover, in situ localization of their transcripts in particular neurosecretory cells (NSCs) in the aphid brain supported the idea that these neuropeptides could correspond to the formerly called virginoparin, an uncharacterized factor originally proposed to be transported directly to the aphid embryos to promote their development as parthenogenetic individuals. To further investigate the fate of these ILPs, we raised a specific antiserum against one of them (ILP4) and mapped this neuropeptide by immunohistochemistry (IHC) in Acyrthosiphon pisum and Megoura viciae aphids. Coincident with in situ localization, our results show that ILP4 is synthesized in two groups (one in each brain hemisphere) of four neurosecretory cells in the pars intercerebralis (NSC group I) and then it is transported outside the brain to the corpora cardiaca. From there, three nerves (two laterals and one medial) transport it to the abdomen. Although no precise site of release has been found, the terminations of these nerves near the germaria would be compatible with the proposal of a direct connection between group I of NSCs and the reproductive system by localized release. In addition, we detected some collateral arborizations originating from the eight NSCs going to the pars lateralis, where clock neurons and some photoreceptors have been previously localized, suggesting a possible communication between the circadian and photoperiodic systems.

Influence of selected biogenic amines on development and demographic parameters of a temperate population of Cinara (Cupressobium) cupressi (Hemiptera, Aphididae)

Cinara (Cupressobium) cupressi, the cypress aphid, is a serious pest of Cupressus spp. and other Cupressaceae, considered to be one of the world’s 100 worst invasive alien species. The potential influence of selected biogenic amines (tryptamine, tyramine, putrescine, and cadaverine) on development and demographic parameters of a temperate population of the cypress aphid was investigated under laboratory conditions. Within parthenogenetic generations, the use of biogenic amines resulted in a significant reduction in the total fecundity and the average daily fecundity both in the fundatrix (F0) and the fundatrigeniae (F1), whereas this influence in the F5 generation was insignificant. In all parthenogenetic generations treated with amines, the dissected female abdomen contained a greater number of mature embryos compared to control samples. Cadaverine caused marked changes in the body length of all viviparous generations studied and a significant reduction in the number of developing embryos, compared to the control sample. The use of biogenic amines did not significantly affect the number of eggs produced by oviparous females but had an impact on their lifespan. Our results indicate that biogenic amines application may disrupt feeding behavior and thus leads to reduced fecundity, consistent with the observation of reduced embryo production. Consequently, bioamines can be used as an alternative agents to control this important pest species.

Peculiarities of the Pontogammarus robustoides (Amphipoda, Gammaridae) Adaptive Reactions to the Water Temperature Increasing in the Model Ecosystem – Microcosm

The crustaceans’ family Gammaridae populations’ adaptive reactions with a water temperature increasing to the critical values were studied in the model ecosystem – the microcosm. The experiment included investigation of such indexes as population dimensional composition, precopulatory activity, number of oviparous females, embryogenesis duration, and energy metabolism at the different phases of thermocycle. Obtained data revealed optimal and critical for gammarid’s viability temperature conditions of environment. It is assumed that under conditions of climate change, when water temperature sharp fluctuations take place, in the Kyiv reservoir (Dnipro River, Ukraine) coastal shallow water crustacean’s family Gammaridae components of the invertebrates associations the structural and functional changes are expected. Temperature increasing to the critical values will promote the animals migration processes intensification; incapable of this animals will perish. Gammarids with ability to migrate in direction of areas with more favorable for their viability conditions will have a significant advantage.

PRESENCE OF NORTH AMERICAN APHID DREPANAPHIS ACERIFOLIAE (THOMAS, 1878) (HEMIPTERA: APHIDIDAE: DREPANOSIPHINAE) IN SERBIA

The painted maple aphid, Drepanaphis acerifoliae (Thomas, 1878), is present on Acer saccharinum L. (silver maple) in Serbia. It was found for the first time in 2019 in parks in Novi Sad, and in 2020 it was registered in Belgrade. It is a North American species that has been extending its distribution in Europe since 1992. Serbia is the fourth European country in which it has been found, following Italy, Spain and Hungary. Drepanaphis acerifoliae was found to be present on all examined A. saccharinum L. trees where it is usually very numerous. It was not found on A. platanoides L., A. campestre L., A. pseudoplatanus L. or A. negundo L. The morphology of viviparous parthenogenetic females, oviparous females and males is presented, with original drawings and photos.