Subsistencia y movilidad de los cazadores-recolectores que ocuparon Cueva TrafulI durante el Holoceno Medio y Tardío.

Se presentan los resultados del análisis del conjunto óseo del Holoceno Medio y tardío de cueva TrafulI (provincia del Neuquén, Argentina). A partir de ellos discutiremos aspectos como la subsistencia y la movilidad de las sociedades cazadoras-recolectoras y la estacionalidad de sus ocupaciones. Las sociedades cazadoras-recolectoras que ocuparon este espacio explotaron recurrentemente al guanaco como parte de sus prácticas de subsistencia. Esta forma de vida se generalizó a mediados del Holoceno, en el ecotono y la estepa, pero siempre se complementó con fauna menor, moluscos, peces o vegetales. En el tránsito de los últimos 2.000 años la cantidad de especies explotadas aumentó significativamente junto con la diversidad. Este fenómeno se debió a la reducción de los rangos de acción mayormente impulsada por la circunscripción territorial de los grupos, que comenzaron a diferenciarse interétnicamente. La incorporación de la tecnología cerámica permitió: diferir el consumo de algunos recursos, extraer más eficientemente la grasa de los huesos y procesar vegetales. Estas condiciones materiales de existencia son interrumpidas por la conquista española. Posteriormente a ésta, la adopción del caballo cambió radicalmente el modo de vida de los cazadores-recolectores pedestres.publishedVersio

Experimental treatments.

<p>11 KA: 11-ketoandrostenedione implants; Empty: empty implants; GSI: gonadal somatic index in females; KSI: kidney somatic index in males. Short day (L8D16) and long day (L16D8) photoperiod.</p

Androgens Increase <i>lws</i> Opsin Expression and Red Sensitivity in Male Three-Spined Sticklebacks

<div><p>Optomotor studies have shown that three-spined sticklebacks (<i>Gasterosteus aculeatus</i>) are more sensitive to red during summer than winter, which may be related to the need to detect the red breeding colour of males. This study aimed to determine whether this change of red light sensitivity is specifically related to reproductive physiology. The mRNA levels of opsin genes were examined in the retinae of sexually mature and immature fish, as well as in sham-operated males, castrated control males, or castrated males implanted with androgen 11-ketoandrostenedione (11 KA), maintained under stimulatory (L16:D8) or inhibitory (L8:D16) photoperiods. In both sexes, red-sensitive opsin gene (<i>lws</i>) mRNA levels were higher in sexually mature than in immature fish. Under L16:D8, <i>lws</i> mRNA levels were higher in intact than in castrated males, and were up-regulated by 11 KA treatment in castrated males. Moreover, electroretinogram data confirmed that sexual maturation resulted in higher relative red spectral sensitivity. Mature males under L16:D8 were more sensitive to red light than males under L8:D16. Red light sensitivity under L16:D8 was diminished by castration, but increased by 11 KA treatment. Thus, in sexually mature male sticklebacks, androgen is a key factor in enhancing sensitivity to red light via regulation of opsin gene expression. This is the first study to demonstrate that sex hormones can regulate spectral vision sensitivity.</p></div

ERG traces of sticklebacks.

<p>Typical ERG traces taken from maximum light stimuli (step 15) for each spectrum. Three repeats are shown. Open arrows indicate the stimuli and solid arrows indicate the presence of <i>b</i>-waves.</p

ERG spectral sensitivities.

<p>Experiment 4; spectral sensitivities of sham-operated males, castrated control males, and castrated males treated with 11-ketoandrostenedione under long day photoperiods, and sham-operated males under a short day photoperiod. Spectral sensitivities were determined through ERG analyses of 5 fish for each group. All data were normalized to the threshold at the most sensitive wavelength (i.e. 500 nm) for each fish. Means ± SEM are shown. *p<0.05.</p

Opsin mRNA levels in castrated and sham-operated males.

<p>Experiment 2; (a) Relative opsin mRNA levels and (b) proportions of cone opsin mRNA levels in castrated (○) and sham-operated (•) males. Means ± SEM are shown. *p<0.05.</p

Sequences of the primers used for PCR and <i>q</i>-PCR.

<p>Efficiency (<i>E_i</i>) (%) for q-PCR primers.</p

Opsin mRNA levels in castrated males treated with androgen.

<p>Experiment 3; effects of castration and androgen treatment on relative (a) <i>rh2</i> and (b) <i>lws</i> mRNA levels, and (c) <i>rh2</i> and (d) <i>lws</i> levels as a proportion of total cone opsin mRNA, under long or short day conditions. Castrated control males (○), castrated males with 11 KA treatment (▵), and sham-operated males (•). Means ± SEM are shown. *p<0.05; **p<0.005.</p