Search results for "Systematics"
showing 10 items of 6702 documents
Pollination ecology of the dioecious tree Commiphora guillauminii in Madagascar
2004
In dioecious plant species differences in morphology and resources between female and male flowers can have consequences for flower visitation rates. Female flowers sometimes lack pollen and can be less attractive to pollinators than male flowers. We studied the pollination ecology of the dioecious tree Commiphora guillauminii in a dry deciduous forest in western Madagascar. We recorded floral display, visiting insect species and visitation rates for female and male trees. The results showed that female trees produce significantly larger but fewer flowers per inflorescence than male ones. Number of flowers per tree did not differ between the sexes. During 270 observation-hours we observed 1…
No evidence for an indirect benefit from female mate preference in Arctic charr Salvelinus alpinus, but female ornamentation decreases offspring viab…
2011
Female mate choice is considered an important evolutionary agent, but there has been an ongoing debate over the fitness consequences it produces, especially in species that have a resource-free mating system. We examined a potential fitness benefit resulting from the pre-spawning mate preference in Arctic charr Salvelinus alpinus, a salmonid fish with no parental care. The females were first allowed to discriminate behaviourally between two males presented to them in a free choice test. We then tested with controlled fertilizations whether the females would accrue indirect genetic benefits for their offspring, as measured by embryonic viability, if they had mated with the male they preferre…
Sex-specific responses to mycorrhiza in a dioecious species.
2011
In most studies about dioecious plants, the role of arbuscular mycorrhizae (AM) and the potential sex-specific differences between the plant hosts have been overlooked. Because plant sexes frequently differ in drought tolerance and AM fungal colonization provides higher resistance to drought, we investigated whether the relation of mycorrhizal fungi with either male or female Antennaria dioica plants differs using a factorial experiment. We hypothesized that because AM usually increase growth rate and male plants usually grow larger than females, males should gain more benefit from the mycorrhizal symbiosis in terms of mineral nutrition and water supply. Because of higher demands of carbohy…
The ecological success of a social parasite increases with manipulation of collective host behaviour.
2015
Many parasites alter the behaviour of their host to their own advantage, yet hosts often vary in their susceptibility to manipulation. The ecological and evolutionary implications of such variation can be profound, as resistant host populations may suffer lower parasite pressures than those susceptible to manipulation. To test this prediction, we assessed parasite-induced aggressive behaviours across 16 populations of two Temnothorax ant species, many of which harbour the slavemaker ant Protomognathus americanus. This social parasite uses its Dufour's gland secretions to manipulate its hosts into attacking nestmates, which may deter defenders away from itself during invasion. We indeed find…
Pre-invasion history and demography shape the genetic variation in the insecticide resistance-related acetylcholinesterase 2 gene in the invasive Col…
2012
Abstract Background Invasive pest species offers a unique opportunity to study the effects of genetic architecture, demography and selection on patterns of genetic variability. Invasive Colorado potato beetle (Leptinotarsa decemlineata) populations have experienced a rapid range expansion and intense selection by insecticides. By comparing native and invasive beetle populations, we studied the origins of organophosphate (OP) resistance-associated mutations in the acetylcholinesterase 2 (AChE2) gene, and the role of selection and demography on its genetic variability. Results Analysis of three Mexican, two US and five European populations yielded a total of 49 haplotypes. Contrary to the exp…
Disassembling Papaver: a restriction site analysis of chloroplast DNA
1992
The results from a chloroplast DNA restriction site analysis of the genera Papaver and Roemeria of subf. Papaveroideae (Papaveraceae) and five outgroup taxa are presented. Papaver is represented by 14 species of eight of the 11 sections recognized, Roemeria by two of its three species. Hunnemannia fumariifolia (subf. Eschscholzioideae), Chelidonium majus (subf. Chelidonioideae), Romneya coulteri, Argemone munita and Stylomecon heterophyllum (all subf. Papaveroideae) were chosen as outgroups. DNAs were digested with 24 restriction enzymes. The major results from this analysis are: 1. Papaver, Roemeria and Stylomecon form a monophyletic group supported by at least 17 restriction site mutation…
Pollen morphology and seed germination studies onRetama raetamssp.gussonei, endemic subspecies from Sicily
2013
A study on pollen morphology and seed germination behaviour of Retama raetam (Forssk.) Webb ssp. gussonei (Webb) Greuter, endemic subspecies from Sicily and Calabria, is herein presented, aiming to preserve these populations strongly affected by anthropic pressure.
Relationships of gag-pol diversity between Ty3/Gypsy and Retroviridae LTR retroelements and the three kings hypothesis
2008
Abstract Background The origin of vertebrate retroviruses (Retroviridae) is yet to be thoroughly investigated, but due to their similarity and identical gag-pol (and env) genome structure, it is accepted that they evolve from Ty3/Gypsy LTR retroelements the retrotransposons and retroviruses of plants, fungi and animals. These 2 groups of LTR retroelements code for 3 proteins rarely studied due to the high variability – gag polyprotein, protease and GPY/F module. In relation to 3 previously proposed Retroviridae classes I, II and II, investigation of the above proteins conclusively uncovers important insights regarding the ancient history of Ty3/Gypsy and Retroviridae LTR retroelements. Resu…
Gypsy endogenous retrovirus maintains potential infectivity in several species of Drosophilids.
2008
Abstract Background Sequences homologous to the gypsy retroelement from Drosophila melanogaster are widely distributed among drosophilids. The structure of gypsy includes an open reading frame resembling the retroviral gene env, which is responsible for the infectious properties of retroviruses. Results In this study we report molecular and phylogeny analysis of the complete env gene from ten species of the obscura group of the genus Drosophila and one species from the genus Scaptomyza. Conclusion The results indicate that in most cases env sequences could produce a functional Env protein and therefore maintain the infectious capability of gypsy in these species.
Distribution of the bilbo Non-LTR Retrotransposon in Drosophilidae and its Evolution in the Drosophila obscura Species Group
2001
The bilbo element is a non-LTR retrotransposon isolated from Drosophila subobscura. We conducted a distribution survey by Southern blot for 52 species of the family Drosophilidae, mainly from the obscura and melanogaster groups. Most of the analyzed species bear sequences homologous to bilbo from D. subobscura. In the obscura group, species from the same species subgroup also share similar Southern blot patterns. To investigate the phylogenetic relationship among these elements, we analyzed eight copies of a short sequence of the element from several species of the obscura group. The obtained phylogram agrees with the phylogeny of the species, which suggests vertical transmission of the ele…