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Insect systemic immune responses to bacterial infections have been mainly studied using microinjections, whereby the microbe is directly injected into the hemocoel. While this methodology has been instrumental in defining immune signaling pathways and enzymatic cascades in the hemolymph, it remains unclear whether and to what extent the contribution of systemic immune defenses to host microbial resistance varies if bacteria invade the hemolymph after crossing the midgut epithelium subsequent to an oral infection. Here, we address this question using the pathogenic Serratia marcescens (Sm) DB11 strain to establish systemic infections of the malaria vector Anopheles gambiae, either by septic Sm injections or by midgut crossing after feeding on Sm. Using functional genetic studies by RNAi, we report that the two humoral immune factors, thioester-containing protein 1 and C-type lectin 4, which play key roles in defense against Gram-negative bacterial infections, are essential for defense against systemic Sm infections established through injection, but they become dispensable when Sm infects the hemolymph following oral infection. Similar results were observed for the mosquito Rel2 pathway. Surprisingly, blocking phagocytosis by cytochalasin D treatment did not affect mosquito susceptibility to Sm infections established through either route. Transcriptomic analysis of mosquito midguts and abdomens by RNA-seq revealed that the transcriptional response in these tissues is more pronounced in response to feeding on Sm. Functional classification of differentially expressed transcripts identified metabolic genes as the most represented class in response to both routes of infection, while immune genes were poorly regulated in both routes. We also report that Sm oral infections are associated with significant downregulation of several immune genes belonging to different families, specifically the clip-domain serine protease family. In sum, our findings reveal that the route of infection not only alters the contribution of key immunity genes to host antimicrobial defense but is also associated with different transcriptional responses in midguts and abdomens, possibly reflecting different adaptive strategies of the host. 

The key to optimizing the performance of an anycast-based sys- tem (e.g., the root DNS or a CDN) is choosing the right set of sites to announce the anycast prefix. One challenge here is predicting catchments. A naïve approach is to advertise the prefix from all subsets of available sites and choose the best-performing subset, but this does not scale well. We demonstrate that by conducting pairwise experiments between sites peering with tier-1 networks, we can predict the catchments that would result if we announce to any subset of the sites. We prove that our method is effective in a simplified model of BGP, consistent with common BGP routing policies, and evaluate it in a real-world testbed. We then present AnyOpt, a system that predicts anycast catchments. Using AnyOpt, a network operator can find a subset of anycast sites that minimizes client latency without using the naïve approach. In an experiment using 15 sites, each peering with one of six transit providers, AnyOpt predicted site catchments of 15,300 clients with 94.7% accuracy and client RTTs with a mean error of 4.6%. AnyOpt identified a subset of 12 sites, announcing to which lowers the mean RTT to clients by 33ms compared to a greedy approach that enables the same number of sites with the lowest average unicast latency. 

The cabbage looper,Trichoplusia ni, is a globally distributed highly polyphagous herbivore and an important agricultural pest.T. nihas evolved resistance to various chemical insecticides, and is one of the only two insect species that have evolved resistance to the biopesticideBacillus thuringiensis(Bt) in agricultural systems and has been selected for resistance to baculovirus infections. We report a 333‐Mb high‐qualityT. nigenome assembly, which has N50 lengths of scaffolds and contigs of 4.6 Mb and 140 Kb, respectively, and contains 14,384 protein‐coding genes. High‐density genetic maps were constructed to anchor 305 Mb (91.7%) of the assembly to 31 chromosomes. Comparative genomic analysis ofT. niwithBombyx morishowed enrichment of tandemly duplicated genes inT. niin families involved in detoxification and digestion, consistent with the broad host range ofT. ni. High levels of genome synteny were found betweenT. niand other sequenced lepidopterans. However, genome synteny analysis ofT. niand theT. niderived cell line High Five (Hi5) indicated extensive genome rearrangements in the cell line. These results provided the first genomic evidence revealing the high instability of chromosomes in lepidopteran cell lines known from karyotypic observations. The high‐qualityT. nigenome sequence provides a valuable resource for research in a broad range of areas including fundamental insect biology, insect‐plant interactions and co‐evolution, mechanisms and evolution of insect resistance to chemical and biological pesticides, and technology development for insect pest management.