COVER Termites (Microcerotermes sp.) explore and consume wood, digesting it in their mound in Far North Queensland, Australia. A globally replicated experiment revealed that wood-feeding termites are far more sensitive to temperature and precipitation compared with wood-dwelling microbes. As temperatures warm, termites are likely to increase recycling rates of deadwood globally, especially in hot, dry places. See page 1440.

Photo: Johan Larson

ONLINE COVER A deep seabed mining vehicle releases sediment plumes nearly two miles below the surface of the Pacific Ocean. An experimental study investigated the dynamics of sediment plumes released by deep sea mining vehicles. Muñoz-Royo et al. examine the in-situ dynamics of the sediment plumes, which could have substantial implications on future plume modeling efforts and our understanding of their impact on the deep-sea environment.

ONLINE COVER Waves of IgA Regulate the Intestinal Microbiota. This month’s cover depicts the dynamic interplay between immunoglobulin A (IgA) and the commensal microbiota in the intestinal lumen. Penny and Domingues et al. report that secretory IgA exhibits daily rhythms in its release from lamina propria plasma cells into the intestinal tract, which are controlled by signals provided by food and the circadian clock. These “waves” of IgA regulate the daily oscillations in the relative abundance of commensal gut microbes to help maintain gut homeostasis.

ONLINE COVER Microrobots Make Big Steps Toward Autonomy. Existing microrobots are generally limited to external control through magnetic fields or light. Microrobots that are able to integrate control, power, and sensing internally (or onboard) are expected to achieve greater autonomy than their externally controlled counterparts. Reynolds et al. have built microscopic robots controlled by onboard complementary metal oxide semiconductor (CMOS) electronics. These microrobots are powered by light and use onboard computers to execute pre-programmed motions. This month’s cover is a false-color scanning electron microscope image of microscopic robots before release.

ONLINE COVER This week, Dolan et al. report that the coordinated mass secretion of mucus by goblet cells and ion transport by enterocytes drive crypt purging in the small intestine. The image is a colorized electron micrograph of a section through the duodenum showing a goblet cell filled with mucus granules and flanked by enterocytes.

ONLINE COVER Overcoming ESR1 Activation. Shown is a carmine alum staining of ductal patterns from whole murine mammary glands of wild type (left) and activating Esr1-mutant (right) mice. The dark structures at the center of the glands are lymph nodes. Liang et al. employed the mouse mammary gland to examine altered estrogen signaling caused by activating mutations in estrogen receptor-1 (ESR1). The authors treated ESR1-mutant patient derived xenografts with giredestrant, a second-generation estrogen receptor-α targeting therapy, which reduced tumor growth. Their study highlights giredestrant as a potential new option for patients with acquired resistance to estrogen-targeting therapies.