Butterfly-Plant Coevolution: Has Passiflora adenopoda Won the Selectional Race with Heliconiine Butterflies?

Hooklike trichomes of Passiflora adenopoda provide a specific, effectively absolute defense against heliconiine butterfly larvae, a major class of Passiflora herbivores. It is suggested that since mechanical defenses are usually more selective in their action against herbivores, they usually are evolved by a plant only after it has accumulated a series of chemical defenses.     

Ovarian Dynamics in Heliconiine Butterflies: Programmed Senescence versus Eternal Youth

New oocytes are generated throughout long lives in butterflies of the genus Heliconius, which as adults feed on amino acids from pollen. In Dryas julia, a related heliconiine that feeds only on nectar and is relatively short-lived, the original oocyte supply is eventually depleted. Such divergent ovarian dynamics in closely related organisms are significant in terms of both their evolutionary basis and their physiological controls.     

Butterfly feeding on lycopsid

Larvae of Euptychia westwoodi feed on Selaginella, a lycopsid. This is the first feeding record in the Satyrinae outside the monocotyledons and one of the few records of a butterfly feeding on other than a seed plant. Clues to possible evolutionary origins of this habit are found in the oviposition behavior of other Euptychia species.     

Comment on "Wandering minds: the default network and stimulus-independent thought"

Mason et al. (Reports, 19 January 2007, p. 393) attributed activity in certain regions of the "resting" brain to the occurrence of mind-wandering. However, previous research has demonstrated the difficulty of distinguishing this type of stimulus-independent thought from stimulus-oriented thought (e.g., watchfulness). Consideration of both possibilities is required to resolve this ambiguity.     

Alpha tocopherol control of sexuality and polymorphism in the rotifer Asplanchna

A dietary component that initiates both the tranisition from parthenogenetic to sexual reproduction and the production of lateral, posterodorsal, and posterior outgrowths of the body wall of females was isolated from the neutral lipids of dried grass and identified as (alpha)-tocopherol. The smallest concentrations eliciting both responses were below 100 nanograms per milliliter. Relative activities of (alpha)-, beta3-, and (gamma)-tocopherol and (alpha)-tocopheryl-quinone were roughly 100 : 100 : 20 : 0.4. The synthetic antioxidants tested were without activity.     

Esterase 6 and reproduction in Drosophila melanogaster

A nonspecific carboxylesterase (esterase 6) of Drosophila melanogaster shows greater activity in adult males than in females and is highly concentrated in the anterior ejaculatory duct of the reproductive tract of the male. Esterase 6 is depleted in males by copulation and is transferred to females early during copulation as a component of the seminal fluid. That esterase 6 may be involved in a system controlling the timing of remating is suggested by differences in the activity of this enzyme in a strain of Drosophila selected for a decrease in time to remating and by differences in the timing of remating in females initially inseminated by males lacking or having active esterase 6.     

B lineage--specific interactions of an immunoglobulin enhancer with cellular factors in vivo

The mouse heavy chain immunoglobulin gene contains a tissue-specific enhancer. The enhancer and flanking sequences were studied in vivo by carrying out dimethyl sulfate protection experiments on living cells, in combination with genomic sequencing. Relative to reactions on naked DNA, there are changes (protections and enhancements) in the reactivity of guanine residues to dimethyl sulfate within the enhancer sequence in myeloma, B, and early B cells, whereas virtually no alterations appear in cells of non-B lineage. Most of the affected residues are in four clusters, in sequences homologous to the octamer 5'CAGGTGGC 3' (C, cytosine; A, adenine; G. guanine; T, thymine). The alterations in the pattern of G reactivity are consistent with the tissue-specific binding of molecules to the mouse immunoglobulin heavy chain enhancer.