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.     

Pollinator attraction in Anacamptis papilionacea (Orchidaceae): a food or a sex promise?

The Mediterranean orchid Anacamptis papilionacea , despite showing a typical food-deceptive floral display, has also been reported to frequently attract male pollinators, suggesting a potentiality for sexual attraction. In a survey from a southern Italian population of A. papilionacea and their hybrids with Anacamptis morio , we collected 37 pollinators belonging to five bee species carrying 126 orchid pollinia. The main pollinator of A. papilionacea was Anthophora crinipes male (48.6%), but the number of females was not negligible (22.9%). We also found pollinator sharing between the hybrid and the parental species. Our findings confirm that, contrary to other food-deceptive species, A. papilionacea mainly attracts male insects, but also that, in contrast to sexually deceptive species, this attraction is not specific. We suggest that A. papilionacea adopts a complex mix of food and sexually deceptive pollination and could represent a helpful model for studying the transition between different pollination strategies.     

The dipteran sperm tail: ultrastructural characteristics and phylogenetic considerations

The sperm tail from representatives of several families of Diptera has been examined by high resolution electron microscopy and a computer analysis that improved the visualization of recorded patterns. A considerable variability in sperm tail structure is found within Diptera, and is actually greater than that of any other insect order. The 'generalized insect sperm axoneme'. which is characterized as a 9+9+2 axoneme and by the accessory microtubules having 16 protofilaments, was found only in some dipterans; these are members of Mycetophilidae. From this fact we conclude that Mycetophilidae is likely to be the most primitive extant dipteran group. Another mycetophilid, Boletina , was seen to have accessory tubules with 15 protofilaments as have members of families Dixidae, Chironomidae, Culicidae, and Bibionidae. The last two families have spermatozoa of a type designated as 9+9+'1' there is a central rod rather than two microtubules. We regard this 9+9+'1'pattern with 15 protofilaments to represent a synapomorphic feature. Representatives of the neatoceran families Tipulidae and Trichoceridae have accessory tubules with 13 protofilaments as do examined members of several brachyceran families. Brachycera is hence likely to be derived from the vicinity of the tipulid family. The intertubular material is small in Mycetophilidae and most nematoceran groups, whereas in Tipulidae and Brachycera it is enlarged; here it bridges the space between the accessory tubules and contains various inclusions.     

Where do Sardinian orchids come from: a putative African origin for the insular population of Platanthera bifolia var. kuenkelei?

Because of the complex geoclimatic dynamics of the Mediterranean basin, resulting from a combination of Tertiary geological processes and Quaternary climatic oscillations, the current species composition of the main continental islands is a mosaic resulting from relative contribution of vicariance, geodispersal and long‐distance dispersal by seed. To help distinguish among the contributions of these different dispersal modes to the orchid species richness on the island of Sardinia, we investigated the genetic structure and phylogeographic relationship of the only Platanthera bifolia var. kuenkelei population on the island. By using plastid DNA sequence variation, we show that this recently discovered population is more closely related to the Tunisian P. bifolia var. kuenkelei than to the geographically closer P. bifolia populations from peninsular Italy. Results from haplotype network construction support the hypothesis that the current distribution of P. bifolia var. kuenkelei (Sardinia and Tunisia) is most likely explained by over‐sea dispersal. However, haplotype diversity and mismatch analysis of this unique Sardinian population suggest that, if a long‐distance dispersal event did occur, it was not recent. More likely, temporarily favourable climatic conditions generated a suitable habitat on the island (also in terms of suitable mycorrhizas and pollinators) and thus a transient opportunity for seedling growth and population establishment of P. bifolia var. kuenkelei from North Africa. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 466–475.