<Emphasis Type="Italic">Pinus radiata</Emphasis> bark extract induces caspase-independent apoptosis-like cell death in MCF-7 human breast cancer cells

In the present study, we investigated the anticancer activity of Pinus radiata bark extract (PRE) against MCF-7 human breast cancer cells. First, we observed that PRE induces potent cytotoxic effects in MCF-7 cells. The cell death had features of cytoplasmic vacuolation, plasma membrane permeabilization, chromatin condensation, phosphatidylserine externalization, absence of executioner caspase activation, insensitivity to z-VAD-fmk (caspase inhibitor), increased accumulation of autophagic markers, and lysosomal membrane permeabilization (LMP). Both the inhibition of early stage autophagy flux and lysosomal cathepsins did not improve cell viability. The antioxidant, n-acetylcysteine, and the iron chelator, deferoxamine, failed to restore the lysosomal integrity indicating that PRE-induced LMP is independent of oxidative stress. This was corroborated with the absence of enhanced ROS production in PRE-treated cells. Chelation of both intracellular calcium and zinc promotes PRE-induced LMP. Geranylgeranylacetone, an inducer of Hsp70 expression, also had no significant protective effect on PRE-induced LMP. Moreover, we found that PRE induces endoplasmic reticulum (ER) stress and mitochondrial membrane depolarization in MCF-7 cells. The ER stress inhibitor, 4-PBA, did not restore the mitochondrial membrane integrity, whereas cathepsin inhibitors demonstrated significant protective effects. Collectively, our results suggest that PRE induces an autophagic block, LMP, ER stress, and mitochondrial dysfunction in MCF-7 cells. However, further studies are clearly warranted to explore the exact mechanism behind the anticancer activity of PRE in MCF-7 human breast cancer cells.     

Taxon-specific prey handling by the loggerhead shrike (<Emphasis Type="Italic">Lanius ludovicianus</Emphasis>)

True Shrikes (Laniidae) are sit-and-wait predators that hunt prey from elevated perches and frequently impale them on sharp objects in conspicuous places. During the 2014 breeding season, we followed a pair of Loggerhead Shrike (Lanius ludovicianus) through their reproductive cycle and documented over 100 h of their behavior on video. On three occasions, the shrikes were observed hunting grasshoppers and in a sequence of very quick stereotypic behaviors, they eviscerated their prey. The shrike held the grasshopper in its feet and with its sharp beak, penetrated the body between the head and the shield-like pronotum, removed the digestive tract in one pull, and then ingested the prey. The removal of the alimentary tract appears to target the anterior portion, specifically the foregut or crop, along with its associated contents. This particular behavior was observed only when grasshoppers were caught but not with other invertebrates. The whole process lasted ca. 5 (±2.6 SD) s.     

Is hissing behaviour of incubating great tits related to reproductive investment in the wild?

Anti-predator behaviour of breeding animals is a complex trait that depends on current reproductive investment as well as individual differences in risk-taking propensities. In response to nest predation, many bird species produce specific sounds, such as the hissing calls in incubating great tits (Parus major), that may provoke an acoustic startle response in the predator. However, it is still unclear whether the propensity of incubating females to produce hissing calls towards nest predators depends on the reproductive investment. With our 3-year study, we show that response type (females that do not hiss versus females giving hissing calls) to a potential nest predator, the woodpecker, is a repeatable trait. We found no differences in the studied reproductive traits between hissing and non-hissing birds. Interestingly, among hissing birds, fast-responding females started egg-laying earlier than slow-responding ones. Among non-hissing birds, heavier birds initiated clutches earlier. We also revealed that hissing birds breed in areas with decreased nest-box occupancy, suggesting either that they potentially select different areas to breed or that territory size is larger as a result of hissing birds being more aggressive. These findings demonstrate that response type is not related to the early reproductive value of the brood across distinct behavioural groups. However, our results do suggest that non-hissing and hissing females differ in terms of individual quality or dominance or personality related aspects.     

The Mating Behavior of an Undescribed Species of <Emphasis Type="Italic">Rhamphomyia</Emphasis> (Diptera: Empididae)

An undescribed sex-role reversed species of an empidid fly in the genus Rhamphomyia exhibits several unusual behavioral features including the early morning and early evening formation of female swarms low in open woodlands, high in treetops, and over grassy hayfields. These swarms only last between 1 and 2 h each and are composed of females with highly ornamented legs that they hold around their narrow abdomens, which they do not inflate in the manner of R. longicauda and some other members of the genus. Males visit the swarms carrying small insects as nuptial gifts that they transfer to the partners they choose as do males of some other sex-role reversed empidids.     

Feeding Kinematics and Nectar Intake of the Honey Bee Tongue

Most flower-visiting insects employ highly-evolved organs to feed themselves rapidly and efficiently on the floral nectar. A honey bee drives its segmented tongue (glossa) covered by dense hairs reciprocatingly to load nectar. A high-speed camera system ameliorated by a microscope revealed morphological changes in glossal surfaces during live honey bees’ nectar dipping and surface configurations through the stretching of postmortem honey bees’ glossae. Both the in vivo and postmortem observations reveal that shortening and lengthening of the glossal segments perform high concordance with the erection of glossal hairs, which aids in developing deformable gaps between rows of glossal hairs during nectar trapping. A model was proposed to evaluate the nectar-intake volume considering the experimentally-measured average erection angle and tongue elongation length during nectar feeding. The theoretical results fit the experimental data well and disclose that these two factors contribute to an augmentation of nectar-intake observably. We also theoretically present that the extendible and deformable glossae have advantages for the polylectic feeding behavior.     

To Smell you Better: Prior Food Deprivation Increases Herbivore Insect Responsiveness to Host Plant Odor Cues

Hunger plays a crucial role in insect feeding behavior, however food deprivation is rarely considered when insect responses to plant host and related chemical stimuli are investigated. Here we assessed, by means of experiments with Y-tube olfactometer, the effect of food deprivation time on the response of a specialist (Xanthogaleruca luteola) and a generalist (Diabrotica speciosa) herbivore beetle species (Coleoptera: Chrysomelidae) to odor cues of their respective host plants. Increasing food deprivation periods enhanced responses to host plant odor in both species, with insects remaining for longer in the olfactometer arm carrying plant odor than in the control, moving less frequently between olfactometer arms, and being more efficient in moving towards the plant odor as their first choice. These trends were less significant in the generalist species, which also required a longer fasting threshold (48 h) in comparison with the specialist (8 h). Our results, showing that prior food deprivation time can influence insect herbivore responsiveness to plant stimuli and that those effects may vary between species, highlight the risk of neglecting this factor in studies involving insect responses to host or chemical stimuli.     

Aggressive Behavior in Olive Fruit Fly Females: Oviposition Site Guarding against Parasitic Wasps

Among Tephritidae flies, the females display agonistic behavior to maintain single oviposition sites and reduce larval competition for food. In the olive fruit fly, Bactrocera oleae, female-female aggressive interactions are characterized by reciprocal wing waving, chasing, head butting and boxing with forelegs. Little is known on tephritid aggressive behaviors directed towards natural enemies, with special reference to parasitoids attacking their young instars. In this study, we quantified the aggressive behavior of B. oleae females guarding their oviposition site against the braconid parasitoid Psyttalia concolor. The fly aggressive behavior displayed against the parasitoids was compared that directed towards paper dummies mimicking P. concolor adults. When a P. concolor female came close (<20 mm) to a B. oleae female guarding the oviposition site, the 91.67% of the flies displayed wing-waving, the 63.34% chased the parasitoid, the 45% showed head-butting, while boxing was observed only in the 26.67% of the aggressions. When paper dummies were tested, only the 66.67% of the flies displayed wing-waving, the 8.33% performed chasing, followed by head butting (5.00%) and boxing (3.33%). B. oleae displayed longer aggression bouts towards live wasps over dummies. Overall, this is the first evidence pointing out that tephritid aggressive acts, besides their role in intraspecific interactions, were also highly effective to displace parasitic wasps from the fly oviposition site. Further research on potential consequences on fitness traits arising from the above-discussed behaviors, as well as on parasitoid learning-mediated responses to tephritid aggressions, is urgently required.     

Influence of Nematode Parasitism,Body Size,Temperature, and Diel Period on the Flight Capacity of <Emphasis Type="Italic">Sirex noctilio</Emphasis> F. (Hymenoptera: Siricidae)

Sirex noctilio F. (Hymenoptera: Siricidae) is a woodwasp of pine trees that has recently invaded and established in North American forests. Although S. noctilio has had a limited impact in North America to date, there is some concern that it could have a significant impact on pine plantations, especially in the southeastern U.S.A. Moreover, there are few data on the flight capacity of male S. noctilio. We found no association between parasitism by D. siricidicola and whether or not S. noctilio initiated flight on the flight mill. Male wasps that were parasitized by nematodes were heavier than non-parasitized males, but there was no significant difference in mass between parasitized and non-parasitized females. We also examined the flight capacity of male and female S. noctilio in relation to nematode parasitism, body mass, temperature (for only males), and diel period. Body mass, temperature, and diel period affected flight in S. noctilio such that wasps were generally observed to fly faster, farther, and more frequently if they were heavier, flying at warmer temperatures, and flying during the photoperiod. The fact that nematode-parasitized male wasps were found to fly farther than the non-parasitized males is consistent with the hypothesis that nematode parasitism does not negatively affect the flight capacity of S. noctilio.     

Does plant size affect growth responses to water availability at glacial,modern and future CO<Subscript>2</Subscript> concentrations?

Plant responses to carbon (C) and water availability are strongly connected. Thus, we can learn much about the responses of modern plants to rising atmospheric carbon dioxide (CO₂) by studying their performance under a range of carbon and water availabilities, including very low CO₂ as in past glacial periods. We hypothesized that, especially in shallow soils, the positive effects of high CO₂ and the negative effects of low CO₂ on growth response to drought are moderated by plant size-driven feedbacks through transpiration and soil water depletion. We grew two temperate annual C₃ species, Avena sativa and Chenopodium album, in glacial (180 ppm), modern (400 ppm) and future (700 ppm) CO₂ levels and five soil water regimes in climate chambers. In both species, low CO₂ resulted in a much lower relative growth rate, biomass and total leaf area than at ambient CO₂ with higher water availability, but this difference disappeared steadily towards severe drought conditions. Elevated CO₂ increased relative growth rate, plant biomass and total leaf area of both species slightly compared with ambient CO₂. These results were especially pronounced under drought. Our results support the hypothesis that, in annuals, plant size modulates the negative drought effect at low CO₂. However, plant size-mediated effects of high CO₂ on growth response to drought were inconclusive. Further experiments should reveal the interactive effects of CO₂ and water regimes in environments closer to a field setting, both in shallow and in deep soils with unconstrained rooting, as well as in mixed communities.