Evolutionary implications of hierarchical impacts of nonlethal injury on reproduction, including maternal effects

Nonlethal injury is pervasive in metazoans, but surprisingly little is known about its impact upon reproductive allocation. The impact of injury on reproduction has been explored in some detail in lizards and salamanders, which have tails that are adapted for fat storage but are also injured or lost during predatory and social encounters. We synthesize diverse insights from these studies and propose new hypotheses using graphical models which highlight three distinct, hierarchical effects of injury on reproduction: reproductive inhibition, reduction in propagule number and diminished per‐propagule investment (PPI), a maternal effect. Previous studies, which involved experimentally amputating the whole tail, have provided evidence of the first two effects, although there is little evidence of reduced PPI. We assayed these effects in free‐ranging Desmognathus salamanders exhibiting naturally occurring injury. Whereas earlier studies found that tail injury prohibits reproduction (precipitating functional conflict), we found that females missing 80% of their tails, including the smallest mature individuals, still reproduce. We also detected a negative correlation between magnitude of injury and PPI, a continuous maternal effect. Continuous (graded) effects of injury on PPI have not been reported previously; neither discrete nor continuous maternal effects due to injury have been previously demonstrated in free‐ranging vertebrates. The dearth of evidence for such effects may be due to the design of experimental manipulations that use all‐or‐nothing treatments. Future studies employing quantitative field data, or more realistic experimental treatments that mimic the continuous distribution of injury are likely to detect maternal effects arising from nonlethal injury. Although our comparative and empirical findings derive from studies of lizards and salamanders, we discuss how they apply in principle to all metazoans. Studies of these effects in nonvertebrate model systems are sorely needed. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86 , 309–331.     

Do inefficient selfing and inbreeding depression challenge the persistence of the rare Dianthus guliae Janka (Caryophyllaceae)? Influence of reproductive traits on a plant's proneness to extinction

The yellow carnation Dianthus guliae Janka is a rare endemic of the Italian peninsula. As numerous extinctions have occurred in the past, very few populations are still present. Two years of field surveys revealed high mortality and an absence of recruitment in the southernmost populations of this species. Work in a botanical garden, under semi-natural conditions, revealed the occurrence of proterandrous hermaphroditism and self-compatibility. The durable flower lifespan, the competitive effects among flowers and the different outcomes from spontaneous and hand-performed pollinations (with both self- and cross-pollen) suggested low pollination rates in the experimental stand. Pollinator exclusion experiments revealed a low frequency of delayed autonomous selfing, suggesting that self-fertilization in D. guliae relies mainly on facilitated selfing and geitonogamy. Studies of inbreeding depression during the early life-history stages revealed significant differences between selfed and crossed progenies in terms of seed mass, germination rates, developmental vigour and mortality rates. Therefore, when pollen delivery is scarce, the plant may fail reproductive assurance via autonomous selfing. The influence of inbreeding depression contributes to a further reduction in recruitment chances in very small D. guliae populations. Experimental reintroductions are urgent to avoid local extinction at the southern periphery of its range.     

Insect immune priming: ecology and experimental evidences

1. Immune priming refers to improved protection of the host after a second encounter with the same parasite or pathogen. This phenomenon is similar to that of adaptive immunity in vertebrates. 2. There is evidence to suggest that this improved protection can be species/strain‐specific and can protect organisms for a lifetime. These two attributes, along with a biphasic immune response, are essential characteristics of immune priming and form the basis for the effectiveness of resistance to parasites and pathogens. 3. This paper considers the effect of immune priming within and across generations, the influence of a heterologous challenge during immune priming and the importance of testing the immune response with natural pathogens. 4. The analysis presented takes into account the multifaceted nature of the invertebrate immune response. The lack of evidence suggesting that the bacterial microbiome plays a complementary role in the immune priming outcome is discussed. 5. Finally, the cost of immune priming is explored. This is a poorly investigated issue, which could help to explain why there is a paucity of evidence in support of immune priming.     

Effects of Continuous SO2 Fumigation on SH-containing Compounds in Two Wheat Cultivars of Different Sensitivities

Two cultivars (Mec and Chiarano) of wheat (Triticum aestivum)were exposed to constant low levels of SO₂ (35, 75 and 120 nll^–1) over a period of 4 months. In previous studies Mechas been shown to be more sensitive to SO₂ and this has beenconfirmed in the present study where Mec showed a greater tendencythan Chiarano to accumulate soluble non-protein SH compounds,principally glutathione and cysteine. The reduced glutathione to oxidized glutathione ratio (GSH/GSSG)increased significantly in Mec with SO₂ treatment, but no changein the activity of glutathione reductase was observed. Key words: Wheat, SO₂ fumigation, SH-compounds     

Limited scope for maternal effects in aphid defence against parasitoids

Abstract.  1. A mother's environment frequently affects her offspring's phenotype. Such maternal effects may be adaptive, in particular with respect to pathogens or parasites, for example if maternal exposure increases offspring resistance.
2. In aphids, maternal effects are likely to occur as a result of their telescoping generations. This study investigated whether maternal effects influence the susceptibility of the peach-potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), to its parasitoid Diaeretiella rapae (M'Intosh) (Hymenoptera: Braconidae: Aphidiinae).
3. In a first experiment, susceptibility was compared among offspring of aphid mothers that had either no contact to parasitoids, had contact but were not attacked, or were attacked but not mummified. Mothers from the last group had successfully resisted the parasitoid.
4. In a second experiment using two different clones, maternal and progeny environment were manipulated by rearing each generation either on a benign (radish) or a more stressful host plant (silver beet) before progeny exposure to parasitoids.
5. The first experiment revealed no significant effect of the maternal treatment on offspring susceptibility to parasitoids and thus no evidence for trans-generational defence. In the second experiment, maternal environment effects were also weak, yet with a trend towards less susceptible offspring of aphid mothers reared on the more stressful plant. However, there was a significant difference among clones and a strong clone × progeny host plant interaction, illustrating that the outcome of a parasitoid attack may be determined by a complex interplay of genetic and environmental factors.
6. Overall, the results suggest that there is limited scope for maternal effects in aphid defence against parasitoids.     

A NEW WIDE-GAUGE SAUROPOD TRACK SITE FROM THE LATE CRETACEOUS OF MENDOZA, NEUQUÉN BASIN, ARGENTINA

Abstract:  Agua del Choique is a new Late Cretaceous sauropod track site from Mendoza Province, Neuquén Basin, Argentina. It is situated in the Loncoche Formation, late Campanian – early Maastrichthian in age, and is one of the youngest sauropod tracks site recorded in the world. Agua del Choique represents a lake setting and river-dominated delta deposits, and comprises at least 160 well-preserved tracks, located on a calcareous sandstone bed. A new ichnotaxon, Titanopodus  mendozensis ichnogen. et ichnosp. nov., is erected for the footprints of this track site. Titanopodus  mendozensis exhibits the following association of features: (1) wide-gauge trackway (manus and pes trackway ratios of 18–22 and 26–31 per cent respectively), (2) pronounced heteropody (manus-pes area ratio of 1:3), (3) outer limits of trackway defined, in some cases, by the manus tracks, and (4) manus impression with an asymmetrical crescent contour and acuminate external border. Titanopodus  mendozensis is an excellent case study of the wide-gauge style of locomotion produced by Late Cretaceous derived titanosaurs that have no impression of manual phalanges. These features, and the fossil record from the Loncoche Formation, suggest that the trackmakers were, probably, middle size saltasaurine or aeolosaurine titanosaurs (14–16 m long).     

Isolation and characterization of polymorphic microsatellite markers in Pagellus bogaraveo,and cross‐species amplification in Sparus aurata and Dicentrarchus labrax

Several new fish species are currently being included in breeding programmes. However, as specific molecular markers have not yet been developed, this represents a commercial handicap with respect to traditional aquaculture species such as gilthead sea bream or Atlantic salmon. In the present study, 12 new microsatellite loci were developed for blackspot sea bream (Pagellus bogaraveo) that show high levels of polymorphism, especially useful in parentage assignment and individual identification. In addition, cross‐amplification was obtained for two important species for Spanish aquaculture, gilthead sea bream and sea bass.     

Testing the regeneration niche hypothesis with Gesneriaceae (tribe Sinningiae) in Brazil: Implications for the conservation of rare species

The germination requirements of sexually reproducing plants are regulated by environmental factors such as temperature. Those factors acting at the germination phase are part of the regeneration niche, which is fundamental in the processes that contribute to habitat suitability and geographic distribution. We tested the hypothesis that rarity is associated with regeneration niche in three species of plants in the family Gesneriaceae (tribe Sinningieae), Sinningia rupicola (Mart.) Wiehler, Paliavana sericiflora Benth and Sinningia allagophylla (Mart.) Wiehler, which vary in their distribution and habitat specificity but share a small zone of sympatry in rocky fields south of Belo Horizonte in Minas Gerais, Brazil. The regeneration niche was tested using a seed germination experiment under controlled light conditions at seven fixed temperatures (10–40°C at 5°C intervals). Each of the three species germinated differently at the various temperatures. The species with the smallest geographic range, S. rupicola, also had the most restricted germination: germination peaked at 15°C when relatively few seeds germinated (45%), and even fewer germinated at other temperatures. The regeneration niche was wider in P. sericiflora and wider still in S. allagophylla, with germination greater than 90% between 15–25°C and greater than 80% between 15–30°C, respectively. Our germination results provide qualified support for the hypothesis of correlation of the regeneration niche with geographic distribution of related plant taxa, with important conservation implications for rare and endangered species.     

Phylogeny and reclassification of Cryptini (Hymenoptera,Ichneumonidae, Cryptinae), with implications for ichneumonid higher‐level classification

The first comprehensive phylogenetic study of the wasp tribe Cryptini (Hymenoptera, Ichneumonidae, Cryptinae) is presented, based on 109 morphological characters and molecular data from seven loci. The dataset includes 370 species, 308 of which are from Cryptini, covering 182 of its 250 genera. Results from parsimony and likelihood analyses are generally congruent. The topology has several implications for ichneumonid higher‐level classification. Previous definitions of the Ichneumoniformes clade are supported, though newly including the Microleptinae. The cryptine subtribe Ateleutina is consistently recovered outside of the Cryptini clade and should be treated as a separate subfamily, Ateleutinae stat.n. The tribe Phygadeuontini is shown to be polyphyletic: while most of the sampled taxa were recovered in a single clade, many of its members are more closely related to the Ichneumoninae, Ateleutinae or Cryptini. Pending a more detailed study, the group should be treated as a separate subfamily, Phygadeuontinae stat. rev . The former Hemigastrini are recovered as largely monophyletic but with important exceptions. Hemigaster Brullé is recovered as part of the Phygadeuontini and is transferred to that group. Echthrus Gravenhorst is consistently recovered as part of Cryptini, rendering Aptesini as the correct name for the tribe. The subfamily Cryptinae should be restricted to the tribes Aptesini and Cryptini. Within Cryptini, the results show little support for the current subtribal classification, with most subtribes recovered as polyphyletic. A number of relatively stable clades are identified and discussed, but the relationships among them are weakly supported. Most of these clades are morphologically heterogeneous and building a subtribal classification based on them would be ineffectual; they are therefore treated under the informal designation of genus groups. The results highlight the ubiquity of morphological homoplasy in Cryptini, and provide a framework from which to address further systematic and evolutionary questions on this hyperdiverse group of parasitic wasps.