Biology subjects

Techer, M. A.

Publications and source records attributed to Techer, M. A..

4 recordsLinked to original sources

bioRxiv2026

Multiple roads to swarming: divergent molecular machineries drive the repeated evolution of locusts

Locust swarming, one of nature's most spectacular examples of a repeated emergent polyphenism, has long been suspected to rely on conserved "swarming genes" or shared genomic features. By applying a model-clade approach comparing six species that vary in their degrees of plasticity and collective behavior, we show that the evolution of swarming locusts is not driven by shared genomic features or a universal set of swarming genes. In contrast, we find that this phenomenon evolved through flexible regulatory architectures, in which the degree of behavioral plasticity directly correlates with the total scale of density-responsive gene expression. While different locust species recruit largely non-overlapping gene sets to achieve the same syndrome, these divergent molecular machineries converge on similar higher-level biological functions. Thus, multiple molecular pathways achieve locust swarming, challenging the preconceived notion about the genetic prerequisites to transition from solitary to collective states. Further, we establish that a complex syndrome such as locust swarming emerges through modular regulatory systems that can be amplified, modified, or attenuated across the tree of life.

evolutionary biology↗

bioRxiv2026

Rearing, dissection, and temporal transcriptomic profiling protocols to study density-dependent phenotypic plasticity in Schistocerca (Insecta: Orthoptera)

This protocol generates gregarious and solitarious density-dependent phenotypes in multiple Schistocerca species under controlled environmental conditions. It describes cage setup, feeding, animal handling, and sterile dissection workflows to isolate nervous, chemosensory, gut, fat body, and female reproductive tissues from nymphs and adults. It emphasizes rapid tissue stabilization and RNase-control practices for downstream single-tissue DNA and RNA analyses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/705994v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@59afdaorg.highwire.dtl.DTLVardef@283b72org.highwire.dtl.DTLVardef@156fa13org.highwire.dtl.DTLVardef@13bf71b_HPS_FORMAT_FIGEXP M_FIG C_FIG

zoology↗

bioRxiv2020

The first steps toward a global pandemic: Reconstructing the demographic history of parasite host switches in its native range

BackgroundHost switching allows parasites to expand their niches. However, successful switching may require suites of adaptations and also may decrease performance on the old host. As a result, reductions in gene flow accompany many host switches, driving speciation. Because host switches tend to be rapid, it is difficult to study them in real-time and their demographic parameters remain poorly understood. As a result, fundamental factors that control subsequent parasite evolution, such as the size of the switching population or the extent of immigration from the original host, remain largely unknown. To shed light on the host switching process, we explored how host switches occur in independent host shifts by two ectoparasitic honey bee mites (Varroa destructor and V. jacobsoni). ResultsBoth switched to the western honey bee (Apis mellifera) after it was brought into contact with their ancestral host (Apis cerana), [~]70 and [~]12 years ago, respectively. Varroa destructor subsequently caused worldwide collapses of honey bee populations. Using whole-genome sequencing on 63 mites collected in their native ranges from both the ancestral and novel hosts, we were able to reconstruct the known temporal dynamics of the switch. We further found multiple previously undiscovered mitochondrial lineages on the novel host, along with the genetic equivalent of tens of individuals that were involved in the initial host switch. Despite being greatly reduced, some gene flow remains between mites adapted to different hosts. ConclusionOur findings suggest that while reproductive isolation may facilitate the fixation of traits beneficial for exploitation of the new host, ongoing genetic exchange may allow genetic amelioration of inbreeding effects.

genomics↗

bioRxiv2019

Genomic analyses of sibling honey bee ectoparasitic mite species show divergent strategies of adaptation

Multispecies host-parasite evolution is common, but how parasites evolve after speciating remains poorly understood. Shared evolutionary history and physiology may propel species along similar evolutionary trajectories whereas pursuing different strategies can reduce competition. We test these scenarios in the economically important association between honey bees and ectoparasitic mites by sequencing the genomes of the sister mite species Varroa destructor and Varroa jacobsoni. These genomes were closely related, with 99.7% sequence identity. Among the 9,628 orthologous genes, 4.8% showed signs of positive selection in at least one species. Divergent selective trajectories were discovered in conserved chemosensory gene families (IGR, SNMP), and Halloween genes (CYP) involved in moulting and reproduction. However, there was little overlap in these gene sets and associated GO terms, indicating different selective regimes operating on each of the parasites. Based on our findings, we suggest that species-specific strategies may be needed to combat evolving parasite communities.

genomics↗