Temporal dissonance between group size and its benefits requires whole-of-lifecycle measurements

Abstract

The benefits of living in groups drive the evolution of sociality, and these benefits could vary across a life-cycle. However, there may be experimental problems in linking group size at one time in a life-cycle to benefits that only become apparent later on when group size has changed, leading to what we call “temporal dissonance”. In the only known social colletid bee, Amphylaeus morosus, parasite pressures arise at various times throughout the life-cycle from different parasitoid species. Amphylaeus morosus is impacted by eight different parasitoid species operating at different host-colony phenology phases, including five species of Gasteruption wasps, a bombyliid fly and two mutillid wasp species. We found that, as the reproductive season progressed, the number of host adults in a nest declined, often to zero, but the presence of even one adult host female during late brood-rearing stages appeared to offer substantial brood protection against mutillids. We propose that the apparent benefits of colony size at one point in time may not reflect the benefits that become apparent at a later point in the season, leading to a temporal dissonance between group size and its later fitness benefits. We also show that A. morosus is strongly protogynous, with variation in parasitoid pressure across the reproductive phenology distorting operational sex ratios away from initial investment ratios. Combined, our data suggest that seasonal variation in parasitoid pressure may have major consequences for understanding social evolution, but these kinds of consequences are largely unexplored in current studies of insect social evolution.

Extreme reproductive skew at the dawn of sociality is consistent with inclusive fitness theory but problematic for routes to eusociality

“…In A. morosus , the indirect fitness benefits for social secondaries exceeded the benefits of reproducing alone (table 2) and demonstrated a significant advantage to social nesting. Amphylaeus morosus is host to a diverse suite of parasitoids that attack at different stages throughout the reproductive season, including severe risk of mortality from mutillid wasps at the end of the season when nests contain full broods [24]. This parasite pressure is likely to be a key driver promoting cooperative nest defence in this species [25].…”

The presence of a guard vicariously drives split sex ratios in a facultatively social bee

“…Brood that had died before nests were opened were not included in pupal weight measurements but were used for NSR calculations. To examine sex allocation patterns across cell positions in the nest, cell position was coded so that 'cell 1' corresponded to the first cell provisioned (furthest from the nest entrance), following Hearn et al [17]. For some analyses, brood that reached adulthood were pooled across all nests and the pupal sex was treated as a binomial response variable (female = 0, male = 1).…”

Research on the Whole Life Cycle of Digital Construction of Power Grid Enterprises based on Product Concept

“…In addition, with the assistance and support of the product concept, compared with the traditional cycle form, the current designed life cycle structure is diversified and specific, with strong pertinence, and can be implemented in a multi-stage manner [7] . Different stages correspond to different digital construction structures, with the daily construction needs or goals of power grid enterprises as the guide, combined with the actual development of enterprises, and overall planning, so as to promote the healthy development of power grid enterprises [8] .…”