Assessment of Variation in Feeding Behavior by Color Morph in the Asian citrus Psyllid (Diaphorini Citri Kuwayama)

The Asian citrus psyllid (ACP) Diaphorina citri (Hemiptera:Liviidae), vector of huanglongbing disease, displays a high degree of color polyphenism. In the adult stage, ACP exhibits abdominal colors that can be separated into three color groupings: blue-green, grey-brown and orange-yellow. Color morphology has been shown to influence important and energetically costly psyllid life traits including reproduction, dispersion, immune defense and resistance to insecticides. Despite this, it remains unclear how color morphology is correlated with feeding behavior. Understanding variation in feeding behavior of the ACP color morphs is critical to better understanding how ACP populations utilize host-plants and to assess potential risk for transmission of the causal agent of huanglongbing disease. We compared the feeding behavior of the three ACP color morphs by using electropenetrography (EPG). We did not detect differences in the feeding behavior activities at phloem or xylem tissues when comparing the three-color morphs. Furthermore, there were no differences in feeding behavioral parameters before reaching phloem or xylem tissues. Our results suggest energy requirements are similar between color morphs and feeding behavior parameters associated with CLas transmission are potentially similar between color morphs.

The first late cretaceous mawsoniid coelacanth (Sarcopterygii: Actinistia) from North America: Evidence of a lineage of extinct ‘living fossils’

Today, the only living genus of coelacanth, Latimeria is represented by two species along the eastern coast of Africa and in Indonesia. This sarcopterygian fish is nicknamed a "living fossil", in particular because of its slow evolution. The large geographical distribution of Latimeria may be a reason for the great resilience to extinction of this lineage, but the lack of fossil records for this genus prevents us from testing this hypothesis. Here we describe isolated bones (right angular, incomplete basisphenoid, fragments of parasphenoid and pterygoid) found in the Cenomanian Woodbine Formation in northeast Texas that are referred to the mawsoniid coelacanth Mawsonia sp. In order to assess the impact of this discovery on the alleged characteristic of "living fossils" in general and of coelacanths in particular: 1) we compared the average time duration of genera of ray-finned fish and coelacanth in the fossil record; 2) we compared the biogeographic signal from Mawsonia with the signal from the rest of the vertebrate assemblage of the Woodbine formation; and 3) we compared these life traits with those of Latimeria. The stratigraphical range of Mawsonia is at least 50 million years. Since Mawsonia was a fresh, brackish water fish with probably a low ability to cross large sea barriers and because most of the continental components of the Woodbine Fm vertebrate assemblage exhibit Laurasian affinities, it is proposed that the Mawsonia’s occurrence in North America is more likely the result of a vicariant event linked to the break-up of Pangea rather than the result of a dispersal from Gondwana. The link between a wide geographic distribution and the resilience to extinction demonstrated here for Mawsonia is a clue that a similar situation existed for Latimeria, which allowed this genus to live for tens of millions of years.

Ectoedemia argyropeza (Zeller, 1839) sur Peuplier Tremble : traits de comportement inférés à partir de la distribution des traces d’activités subsistant sur les feuilles-hôtes (Lepidoptera, Nepticulidae)

Ectoedemia argyropeza on Aspen leaves: deciphering retrospectively some behavioural traits from the distribution of traces of the insect activities subsisting on host-leaves (Lepidoptera, Nepticulidae). Despite their usually small size, endotrophic insects —especially those whose larvae are mining into their host-leaves— exhibit patterns of behaviour that are often more elaborate than what is usually seen in many ectotrophic herbivorous insects. However, since it is generally difficult to capture properly these behaviours in the field, precisely due to the small size of these insects, it turns out to be more convenient attempting to uncover retrospectively some of these behaviours on the basis of their resulting traces which subsist on the host-leaves. In order to be able to infer reliable information from this retrospective approach, the examination of a substantial number of host leaves and the support of appropriate statistical tests are required. The present study concerns a species of microlepidoptera, Ectoedemia argyropeza, whose caterpillars are exclusively mining the leaves of Aspen (Populus tremula) and which is still further distinguished, in a remarkable manner, by the induction of a preliminary galling (“cecidian”) development stage. This unusual combination of life traits contributes to enrich the insect’s behavioural repertoire and therefore offers a more promising field of investigation. For this species, I more particularly focus on the way the artefacts resulting from the insect activities are distributed spatially, on (or in) the host leaf, namely: (i) the spatial distribution of eggs deposited on the host-leaf petiole, (ii) the hierarchy of preferential positioning of the caterpillar corridor in the section of the petiole, hypertrophied by the cecidogenic reaction, (iii) the hierarchy of preferential locations of mines in the host-leaf blade. Were also tested, on the one hand, the existence (or not) of paired relationships between each of the three categories of distributions mentioned above and, on the other hand, the degree of conformation of each of these different distributions to the bilateral symmetry of the leaf support. The behavioural aspects that can be tentatively inferred from the above information are subsequently discussed.

Aedes aegypti continuously exposed to Bacillus thuringiensis svar. israelensis does not exhibit changes in life traits but displays increased susceptibility for Zika virus

Background Aedes aegypti can transmit arboviruses worldwide, and Bacillus thuringiensis svar. israelensis (Bti)-based larvicides represent an effective tool for controlling this species. The safety of Bti and lack of resistance have been widely reported; however, little is known regarding the impact of the extensive use of these larvicides on the life traits of mosquitoes. Therefore, this study investigated biological parameters, including susceptibility to arbovirus, of an Ae. aegypti strain (RecBti) subjected to 29 generations of exposure to Bti compared with the RecL reference strain. Methods The biological parameters of individuals reared under controlled conditions were compared. Also, the viral susceptibility of females not exposed to Bti during their larval stage was analysed by oral infection and followed until 14 or 21 days post-infection (dpi). Results RecBti individuals did not display alterations in the traits that were assessed (fecundity, fertility, pupal weight, developmental time, emergence rate, sex ratio and haematophagic capacity) compared to RecL individuals. Females from both strains were susceptible to dengue serotype 2 (DENV-2) and Zika virus (ZIKV). However, RecBti females showed significantly higher rates of ZIKV infection compared with RecL females at 7 (90% versus 68%, Chi-square: χ2 = 7.27, df = 1, P = 0.006) and 14 dpi (100% versus 87%, Chi-square: χ2 = 7.69, df = 1, P = 0.005) and for dissemination at 7 dpi (83.3% versus 36%, Fisher’s exact test: P < 0.0001, OR = 0.11, 95% CI 0.03–0.32). Quantification of DENV-2 and ZIKV viral particles produced statistically similar results for females from both strains. Conclusions Prolonged exposure of Ae. aegypti larvae to Bti did not alter most of the evaluated biological parameters, except that RecBti females exhibited a higher vector susceptibility for ZIKV. This finding is related to a background of Bti exposure for several generations but not to a previous exposure of the tested females during the larval stage. This study highlights mosquito responses that could be associated with the chronic exposure to Bti in addition to the primary larvicidal effect elicited by this control agent. Graphical abstract

The Heritability of Behaviors Associated With the Host Gut Microbiota

What defines whether the interaction between environment and organism creates a genetic memory able to be transferred to subsequent generations? Bacteria and the products of their metabolism are the most ubiquitous biotic environments to which every living organism is exposed. Both microbiota and host establish a framework where environmental and genetic factors are integrated to produce adaptive life traits, some of which can be inherited. Thus, the interplay between host and microbe is a powerful model to study how phenotypic plasticity is inherited. Communication between host and microbe can occur through diverse molecules such as small RNAs (sRNAs) and the RNA interference machinery, which have emerged as mediators and carriers of heritable environmentally induced responses. Notwithstanding, it is still unclear how the organism integrates sRNA signaling between different tissues to orchestrate a systemic bacterially induced response that can be inherited. Here we discuss current evidence of heritability produced by the intestinal microbiota from several species. Neurons and gut are the sensing systems involved in transmitting changes through transcriptional and post-transcriptional modifications to the gonads. Germ cells express inflammatory receptors, and their development and function are regulated by host and bacterial metabolites and sRNAs thus suggesting that the dynamic interplay between host and microbe underlies the host’s capacity to transmit heritable behaviors. We discuss how the host detects changes in the microbiota that can modulate germ cells genomic functions. We also explore the nature of the interactions that leave permanent or long-term memory in the host and propose mechanisms by which the microbiota can regulate the development and epigenetic reprogramming of germ cells, thus influencing the inheritance of the host. We highlight the vast contribution of the bacterivore nematode C. elegans and its commensal and pathogenic bacteria to the understanding on how behavioral adaptations can be inter and transgenerational inherited.

Reproductive and Developmental Biology of Acroclisoides sinicus, a Hyperparasitoid of Scelionid Parasitoids

Acroclisoides sinicus (Hymenoptera: Pteromalidae) was described in 1988 from China, but recent findings in Europe and North America within the framework of Halyomorpha halys (Hemiptera: Pentatomidae) biological control indicate a Holarctic distribution. The few records and fragmented information on A. sinicus are derived from generic observations of other species belonging to the same genus, and its biological and ethological traits are still completely unexplored. It was suspected to be a facultative or obligate hyperparasitoid of many egg parasitoid species (e.g., Scelionidae and Eupelmidae), especially those parasitizing Pentatomidae eggs. Laboratory colonies of A. sinicus were established from specimens collected in the field in Europe and the USA, which allowed us to investigate for the first time the life traits of this somewhat enigmatic species. Our studies confirmed the obligate hyperparasitoid hypothesis for species of Scelionidae but not of Eupelmidae. Laboratory studies revealed that A. sinicus is extremely selective in its host recognition as only the pupal stage of its host species is exploited for parasitization. Taking into consideration its hyperparasitoid habit, the adventive A. sinicus populations in Europe and North America may potentially be severe threats to pentatomid natural control as new components in the trophic chain of pentatomids and their parasitoid guilds.

Effect of plant protection on assemblages of ground beetles (Coleoptera, Carabidae) in sugar beet crops in four-year rotation

The influence of chemical plant protection on carabid beetle assemblages was studied in an experiment conducted on fields of sugar beet at the IOR-PIB Experimental Station in Winna Góra, Poland. The experiment was composed of a block of control fields (no chemical plant protection treatments) and second block, where plant protection was carried out in compliance with the applicable plant protection program. Ground beetles were caught from May to August/September in four years, using modified Barber traps. As a result of the study, 11 881 specimens belonging to 52 species of Carabidae were collected. The most numerous species were: Harpalus rufipes, Pterostichus melanarius, Calathus ambiguus and Bembidion properans. Overall, our results demonstrate that the application of chemical plant protection treatments decreased the abundance of carabid beetles in sugar beet fields, but had no effect on species richness. The use of pesticides induced changes in some life traits of Carabidae fauna. After a pesticide application, the abundance of macropterous hemizoophages and medium carnivores with the autumn type of breeding decreased, whereas the abundance of small carnivores increased.

Utopian Elements in Porphyry’s De abstinentia

In the long passage of De abstinentia, IV, 2–18, Porphyry mentions a series of “groups” (ἔθνη) as examples of abstinence from animal food: the ancient Greeks of the “golden age”, the Lacedaemonians of Lycurgus’ era, the Egyptian priests, the Essenes among the Jews, the Magi among the Persians and the gymnosophists among the Indians. Such an association does not seem at all accidental, since Porphyry refers to a tradition in which these communities have similar habits of life, including the prohibition of eating meat and drinking wine, sexual abstinence, absence of diseases and wars, separation from the civil sphere, devotion to the sacred. All these elements constitute the specific connotation of a human existence that evokes the “time of the origins”, substantially a paradisiac dimension, far from history. It is a deliberate symbolic shift. This brief research will investigate the reasons and the deep meaning of the connection based on utopian life traits.