Marriage Systems and Pathogen Stress in Human Societies

Pathogen stress is an important form of environmental extremenessand uncertainty for humans as well as other organisms. It ispredicted to: fl] increase the degree of polygyny (as fewermales become appropriate mates); [2] make non-sororal polygynymore frequent (as variable offspring become more advantageous),and [3] be correlated with signs of sexual selection: physicaldimorphism, societal rules about allowed wives for men in differentcategories, both achieved and inherited. The first two hypotheses are supported. As pathogen stress increases,the degree of polygyny increases, no matter how polygyny ismeasured. As pathogen stress increases, non-sororal polygynyand capture of women from outside societies increase; sororaland other endogamous forms of polygyny decrease. The third hypothesisis not supported. Measures of male-male competition and reflectionsof male status are not associated with pathogen stress. A man'sactual present appearance (physical, behavioral) may providea more direct and accurate reflection of a man's worth as amate. It is possible that the measures available for testinghere are not fully appropriate. These results suggest that major pathogens may have been, duringhuman evolutionary history, an important selective force, shiftingthe polygyny threshold, and resulting in greater polygyny, andpolygyny of specific types, in areas of high stress. The relationshipappears to be of a threshold sort (at high levels of pathogenstress monogamy, polyandry, and mild polygyny are absent) ratherthan a linear relationship. We need within-society data forappropriate pathogens regarding relationship between individualpathogen load and probability of getting a mate, possible interactionsbetween pathogen stress and resource accumulation in sexualselection, and impact of pathogen load on fertility.     

Indigenous Architecture and the Spanish American Plaza in Mesoamerica and the Caribbean

Plazas are often important spatial representations of society and social hierarchy. Those built in Mesoamerica and the Caribbean under the direction of the Spanish have been interpreted as architectural representations of colonial control and oppression. Underlying these interpretations is the tacit assumption that plaza-centered urban design was of solely European derivation, in spite of considerable evidence of pre-Columbian contributions. In fact, the correspondence between the indigenous forms and Spanish reconstruction is so well documented that the denial of its significance is startling.     

Elevated volatile concentrations in high‐nutrient plants: do insect herbivores pay a high price for good food?

1. A tritrophic perspective is fundamental for understanding the drivers of insect–plant interactions. While host plant traits can directly affect insect herbivore performance by either inhibiting or altering the nutritional benefits of consumption, they can also have an indirect effect on herbivores by influencing rates of predation or parasitism. 2. Enhancing soil nutrients available to trees of the genus Eucalyptus consistently modifies plant traits, typically improving the nutritional quality of the foliage for insect herbivores. We hypothesised that resulting increases in volatile essential oils could have an indirect negative effect on eucalypt‐feeding herbivores by providing their natural enemies with stronger host/prey location cues. 3. Eucalyptus tereticornis Smith seedlings were grown under low‐ and high‐nutrient conditions and the consequences for the release of volatile cues from damaged plants were examined. The influence of 1,8‐cineole (the major volatile terpene in many Eucalyptus species) on rates of predation on model caterpillars in the field was then examined. 4. It was found that the emission of cineole increased significantly after damage (artificial or herbivore), but continued only when damage was sustained by herbivore feeding. Importantly, more cineole was emitted from high‐ than low‐nutrient seedlings given an equivalent amount of damage. In the field, predation was significantly greater on model caterpillars baited with cineole than on unbaited models. 5. These findings are consistent with the hypothesis that any performance benefits insect herbivores derive from feeding on high‐nutrient eucalypt foliage could be at least partially offset by an increased risk of predation or parasitism via increased emission of attractive volatiles.     

Floral Nectar Secretion and Ploidy in Brassica rapa and B. napus (Brassicaceae). II. Quantified Variability of Nectary Structure and Function in Rapid-cycling Lines

Haploid, diploid and tetraploid lines ofBrassica rapaL. (syn.campestris),and allotetraploidB. napusL., were examined to determine theinfluence of ploidy on floral features, particularly nectarymorphology and anatomy, and to relate nectary structure to nectarproduction capacity. Except for haploids, all lines were rapid-cycling.Average flower dry weight, and petal length and width, werein the descending orderB. napus>B. rapa (4n) >2n>n.Pollen grains of 4nplants were larger than those of 2nplants;haploids lacked pollen. All lines developed nectaries. Typically, each flower producedtwo pairs of nectaries, of different types and nectar productioncapacity. Normally, each lateral gland was located above thebase of a short stamen, and together this pair yielded mostof a flower 's nectar carbohydrate. Each median nectary aroseat the outer junction of the bases of two adjacent long stamens.All lateral nectaries received a vascular supply of phloem alone,but median glands received reduced amounts of phloem, or lackedvasculature altogether. Most nectaries were solitary, but 14%of all flowers, and especially those of 2n B. rapa,had at leastone median and lateral gland connected. Obvious variation existed in nectary morphology between ploidylevels, between flowers of the same plant, and even within flowers.Ten forms of each nectary type were recognized. Plants producingthe most nectar carbohydrate had high frequencies of lateralnectaries which were symmetrical, unfurrowed swellings. TetraploidsofB. rapahad both the highest frequencies of furrowed lateralglands, and of isolated segments of nectarial tissue at thatposition. Even these separated nectarial outgrowths receivedphloem and produced a nectar droplet. At the median location,nectaries were commonly of two forms: peg- or fan-shaped. Lobeson median nectaries, up to four per nectary, were detected inalmost half of glands of 4nflowers examined; lobes were absentin haploids. Brassica rapa; Brassica napus; flower size; nectar production; nectary variability; petal size; ploidyphloem; pollen; rapeseed