42 research outputs found
Synchronisation of egg hatching of brown hairstreak (Thecla betulae) and budburst of blackthorn (Prunus spinosa) in a warmer future
Synchronisation of the phenology of insect herbivores and their larval food plant is essential for the herbivores’ fitness. The monophagous brown hairstreak (Thecla betulae) lays its eggs during summer, hibernates as an egg, and hatches in April or May in the Netherlands. Its main larval food plant blackthorn (Prunus spinosa) flowers in early spring, just before the leaves appear. As soon as the Blackthorn opens its buds, and this varies with spring temperatures, food becomes available for the brown hairstreak. However, the suitability of the leaves as food for the young caterpillars is expected to decrease rapidly. Therefore, the timing of egg hatch is an important factor for larval growth. This study evaluates food availability for brown hairstreak at different temperatures. Egg hatch and budburst were monitored from 2004 to 2008 at different sites in the Netherlands. Results showed ample food availability at all monitored temperatures and sites but the degree of synchrony varied strongly with spring temperatures. To further study the effect of temperature on synchronisation, an experiment using normal temperatures of a reference year (T) and temperatures of T + 5°C was carried out in climate chambers. At T + 5°C, both budburst and egg hatch took place about 20 days earlier and thus, on average, elevated temperature did not affect synchrony. However, the total period of budburst was 11 days longer, whereas the period of egg hatching was 3 days shorter. The implications for larval growth by the brown hairstreak under a warmer climate are considered.
Old lineage on an old island : Pixibinthus, a new cricket genus endemic to New Caledonia shed light on gryllid diversification in a hotspot of biodiversity
Few studies have focused on the early colonization of New Caledonia by insects, after the re-emergence of the main island, 37 Myr ago. Here we investigate the mode and tempo of evolution of a new endemic cricket genus, Pixibinthus, recently discovered in southern New Caledonia. First we formally describe this new monotypic genus found exclusively in the open shrubby vegetation on metalliferous soils, named 'maquis minier', unique to New Caledonia. We then reconstruct a dated molecular phylogeny based on five mitochondrial and four nuclear loci in order to establish relationships of Pixibinthus within Eneopterinae crickets. Pixibinthus is recovered as thesister clade of the endemic genus Agnotecous, mostly rainforest-dwellers. Dating results show that the island colonization by their common ancestor occurred around 34.7 Myr, shortly after New Caledonia re-emergence. Pixibinthus and Agnotecous are then one of the oldest insect lineages documented so far for New Caledonia. This discovery highlights for the first time two clear-cut ecological specializations between sister clades, as Agnotecous is mainly found in rainforests with 19 species, whereas Pixibinthus is found in open habitats with a single documented species. The preference of Pixibinthus for open habitats and of Agnotecous for forest habitats nicely fits an acoustic specialization, either explained by differences in body size or in acoustic properties of their respective habitats. We hypothesize that landscape dynamics, linked to major past climatic events and recent change in fire regimes are possible causes for both present-day low diversity and rarity in genus Pixibinthus. The unique evolutionary history of this old New Caledonian lineage stresses the importance to increase our knowledge on the faunal biodiversity of 'maquis minier', in order to better understand the origin and past dynamics of New Caledonian biota
Integrated Mapping, Chromosomal Sequencing and Sequence Analysis of Cryptosporidium parvum
The apicomplexan Cryptosporidium parvum is one of the most prevalent protozoan parasites of humans. We report the physical mapping of the genome of the Iowa isolate, sequencing and analysis of chromosome 6, and ∼0.9 Mbp of sequence sampled from the remainder of the genome. To construct a robust physical map, we devised a novel and general strategy, enabling accurate placement of clones regardless of clone artefacts. Analysis reveals a compact genome, unusually rich in membrane proteins. As in Plasmodium falciparum, the mean size of the predicted proteins is larger than that in other sequenced eukaryotes. We find several predicted proteins of interest as potential therapeutic targets, including one exhibiting similarity to the chloroquine resistance protein of Plasmodium. Coding sequence analysis argues against the conventional phylogenetic position of Cryptosporidium and supports an earlier suggestion that this genus arose from an early branching within the Apicomplexa. In agreement with this, we find no significant synteny and surprisingly little protein similarity with Plasmodium. Finally, we find two unusual and abundant repeats throughout the genome. Among sequenced genomes, one motif is abundant only in C. parvum, whereas the other is shared with (but has previously gone unnoticed in) all known genomes of the Coccidia and Haemosporida. These motifs appear to be unique in their structure, distribution and sequences
The genome of Desulfotalea psychrophila, a sulfate-reducing bacterium from permanently cold Arctic sediments
Desulfotalea psychrophila is a marine sulfate-reducing delta-proteobacterium that is able to grow at in situ temperatures below 0 degrees C. As abundant members of the microbial community in permanently cold marine sediments, D. psychrophila-like bacteria contribute to the global cycles of carbon and sulfur. Here, we describe the genome sequence of D. psychrophila strain LSv54, which consists of a 3 523 383 bp circular chromosome with 3118 predicted genes and two plasmids of 121 586 bp and 14 663 bp. Analysis of the genome gave insight into the metabolic properties of the organism, e.g. the presence of TRAP-T systems as a major route for the uptake of C(4)-dicarboxylates, the unexpected presence of genes from the TCA cycle, a TAT secretion system, the lack of a beta-oxidation complex and typical Desulfovibrio cytochromes, such as c(553), c(3) and ncc. D. psychrophila encodes more than 30 two-component regulatory systems, including a new Ntr subcluster of hybrid kinases, nine putative cold shock proteins and nine potentially cold shock-inducible proteins. A comparison of D. psychrophila's genome features with those of the only other published genome from a sulfate reducer, the hyperthermophilic archaeon Archaeoglobus fulgidus, revealed many striking differences, but only a few shared features
The genome of Desulfotalea psychrophila, a sulfate-reducing bacterium from permanently cold Arctic sediments
Desulfotalea psychrophila is a marine sulfate-reducing delta-proteobacterium that is able to grow at in situ temperatures below 0 degrees C. As abundant members of the microbial community in permanently cold marine sediments, D. psychrophila-like bacteria contribute to the global cycles of carbon and sulfur. Here, we describe the genome sequence of D. psychrophila strain LSv54, which consists of a 3 523 383 bp circular chromosome with 3118 predicted genes and two plasmids of 121 586 bp and 14 663 bp. Analysis of the genome gave insight into the metabolic properties of the organism, e.g. the presence of TRAP-T systems as a major route for the uptake of C(4)-dicarboxylates, the unexpected presence of genes from the TCA cycle, a TAT secretion system, the lack of a beta-oxidation complex and typical Desulfovibrio cytochromes, such as c(553), c(3) and ncc. D. psychrophila encodes more than 30 two-component regulatory systems, including a new Ntr subcluster of hybrid kinases, nine putative cold shock proteins and nine potentially cold shock-inducible proteins. A comparison of D. psychrophila's genome features with those of the only other published genome from a sulfate reducer, the hyperthermophilic archaeon Archaeoglobus fulgidus, revealed many striking differences, but only a few shared features
Scientists' warning to humanity on insect extinctions
Here we build on the manifesto ‘World Scientists’ Warning to Humanity, issued by the Alliance of World Scientists. As a group of conservation biologists deeply concerned about the decline of insect populations, we here review what we know about the drivers of insect extinctions, their consequences, and how extinctions can negatively impact humanity.
We are causing insect extinctions by driving habitat loss, degradation, and fragmentation, use of polluting and harmful substances, the spread of invasive species, global climate change, direct overexploitation, and co-extinction of species dependent on other species.
With insect extinctions, we lose much more than species. We lose abundance and biomass of insects, diversity across space and time with consequent homogenization, large parts of the tree of life, unique ecological functions and traits, and fundamental parts of extensive networks of biotic interactions. Such losses lead to the decline of key ecosystem services on which humanity depends. From pollination and decomposition, to being resources for new medicines, habitat quality indication and many others, insects provide essential and irreplaceable services. We appeal for urgent action to close key knowledge gaps and curb insect extinctions. An investment in research programs that generate local, regional and global strategies that counter this trend is essential. Solutions are available and implementable, but urgent action is needed now to match our intentions
Habitat quality determines patch occupancy of two specialist Lepidoptera species in well-connected grasslands
Landscape-scale effects of Christmas-tree plantations in an intensively used low-mountain landscape – Applying breeding bird assemblages as indicators
Solutions for humanity on how to conserve insects
The fate of humans and insects intertwine, especially through the medium of plants. Global environmental change, including land transformation and contamination, is causing concerning insect diversity loss, articulated in the companion review Scientists' warning to humanity on insect extinctions. Yet, despite a sound philosophical foundation, recognized ethical values, and scientific evidence, globally we are performing poorly at instigating effective insect conservation. As insects are a major component of the tapestry of life, insect conservation would do well to integrate better with overall biodiversity conservation and climate change mitigation. This also involves popularizing insects, especially through use of iconic species, through more media coverage, and more inclusive education. Insect conservationists need to liaise better with decision makers, stakeholders, and land managers, especially at the conceptually familiar scale of the landscape. Enough evidence is now available, and synthesized here, which illustrates that multiple strategies work at local levels towards saving insects. We now need to expand these locally-crafted strategies globally. Tangible actions include ensuring maintenance of biotic complexity, especially through improving temporal and spatial heterogeneity, functional connectivity, and metapopulation dynamics, while maintaining unique habitats, across landscape mosaics, as well as instigating better communication. Key is to have more expansive sustainable agriculture and forestry, improved regulation and prevention of environmental risks, and greater recognition of protected areas alongside agro-ecology in novel landscapes. Future-proofing insect diversity is now critical, with the benefits far reaching, including continued provision of valuable ecosystem services and the conservation of a rich and impressive component of Earth's biodiversity